2011 ISSUE 2

SCIENCE & TECHNOLOGY AT THE AMES LABORATORY

Danny Shechtman

2011 Nobel Prize 

in Chemistry 
FEATURES

The Ames Laboratory is a U.S. Department 

of Energy national laboratory seeking 

solutions to energy-related problems through 

the exploration of chemical, engineering, 

materials and mathematical sciences, and 

physics. Established in the 1940s with 

the successful development of the most 

efficient process to produce high-purity 

uranium metal for atomic energy, Ames Lab 

now pursues much broader priorities than 

the materials research that has given the 

Lab international credibility. Responding to 

issues of national concern, Ames Laboratory 

scientists are actively involved in innovative 

research, science education programs, the 

development of applied technologies and 

the quick transfer of such technologies 

to industry. Uniquely integrated within a 

university environment, the Lab stimulates 

creative thought and encourages scientific 

discovery, providing solutions to complex 

problems and educating and training 

tomorrow’s scientific talent.

Steve Karsjen, Public Affairs Director

Kerry Gibson, Editor

Breehan Gerleman Lucchesi,

Contributing Editor

Grant Luhmann, Art Director

Copyright 2011 by the Ames Laboratory. 

All rights reserved. For additional information about the Ames Laboratory or topics 

covered in this publication, please contact: 

Editor, Inquiry

Ames Laboratory

111 TASF

Ames, Iowa 50011-3020

515-294-9557

www.ameslab.gov

Inquiry is published biannually 

by the Ames Laboratory Office of 

Public Affairs. Iowa State University 

operates the Laboratory for the 

U.S. Department of Energy under 

contract DE AC02 07CH11358. 

Contents

Cover: Danny Shechtman’s Nobel Prize in Chemistry for the discovery of quasicrystals was 

also the impetus behind discoveries by other Ames Laboratory scientists. Pat Thiel’s work on 

surface structure resulted in the development of the blue, five-fold symmetry pattern shown in 

the small inset. Paul Canfield helped prove the existence of quasicrystals by growing a large, 

single crystal of holmium-magnesium-zinc (Ho-Mg-Zn) that clearly shows five-fold symmetry. Alan Goldman captured the X-ray diffraction image of a scandium-zinc quasicrystal that 

shows the same 10-dot pattern that Shechtman first witnessed. A larger version of Goldman’s 

image appears on the back cover. ENERGY

U.S. DEPARTMENT OF Office of

Science

8

10

Battin’ a Thousand 

When it comes to attracting Science Undergraduate Laboratory 

Internship program students to attend graduate school at Iowa 

State University, Ames Lab senior scientist Mark Gordon has a 

perfect record.

Characterization

The Ames Laboratory has a wealth of expertise in a wide variety 

of characterization techniques so that the properties of new 

materials can be quickly determined and that feedback used to 

tweak compositions to enhance the desirable characteristics.

Anomaly Results in Nobel Prize

A characterization anomaly brought criticism and derision to 

Danny Shechtman, but eventually resulted in a Nobel Prize in 

chemistry for the Ames Laboratory scientist.

Laser-guided Discovery

Ames Laboratory scientist Emily Smith is using a tool called 

Raman spectroscopy to help unlock the secrets of efficiently 

converting plant material into biofuels.

Uncharted Territory

Ames Lab scientist Tanya Prozorov is hoping to break new 

ground by using transmission electron microscopy to determine how bio-inspired magnetic nanocrystals form.

Scattering at the Ames Laboratory

Ames Lab physicists use neutron and X-ray scattering to help 

map out the properties of new materials, such as iron-arsenide superconductors.

Power of Nanomachines

Tracking tiny gold nanorods using optical microscopy helps 

Ames Lab chemists understand tiny motions in living cells.

Nanosized Look at Rare-earth Graphene Bonds

Graphene may be the key to super-small electronics, so Ames 

Lab scientists are using scanning tunneling microscopy to understand how graphene and metals interact at the nanoscale.

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From the Director

INQUIRY Issue 2 • 2011 3

s this issue of Inquiry was being put together, 

we learned that our colleague Danny Shechtman had been 

awarded the 2011 Nobel Prize in Chemistry for the discovery 

of quasicrystals. This stunning discovery was based entirely on 

a single observation made using a transmission electron microscope - one 

of the workhorse tools of materials characterization. Much controversy followed the initial discovery, and the Ames Lab played a large role in settling 

the arguments in favor of the assertion that materials had been discovered 

with five-fold symmetry. Some of the iconic images from this work are 

shown as insets on our cover. The story of the discovery, and eventual 

acceptance of quasicrystals, rests very much upon sophisticated, advanced 

materials characterization, sometimes using techniques invented or modified “on the fly” to cope with the challenges of the unexpected discovery. 

The Ames Laboratory has a unique ability to create materials. Theory, 

computation and not a little scientific instinct all come together here and allow us to invent new materials for 

energy applications. The Ames Lab also has world-leading capabilities for making the materials that it designs, 

to prove that the designs work. (We try very hard not to contribute to the ever-growing list of theoretically 

wonderful materials that cannot actually be made.)

But once you have designed a new material and made some of it, what do you do next?

Materials characterization is used to determine the properties of a material, from its chemical composition 

to its structure, its thermodynamic, mechanical, electrical, optical, magnetic and other properties, its chemical 

properties, and even the details of how electrons interact with each other inside it or on its surfaces.

Because we make materials that sometimes have novel or exotic properties, we also have a high investment in world-leading materials characterization to probe and explore those properties. When the Ames Lab 

first started, its job was to purify uranium metal, and it quickly developed chemical-analysis tools to characterize 

the purity of the product, resulting in some of the most sensitive chemical analysis techniques used in the 

world today. As we focus on ever more complex materials, 

we still work on a parallel path to develop the capability to 

characterize them. The result is that we have world-leading 

research on tools like solid-state nuclear magnetic resonance 

(see Inquiry, 2009 issue 2) and angle-resolved photo-electron spectrometry.

In this issue of Inquiry, we are providing an update on 

some of the materials characterization tools and techniques 

under development at the Ames Lab. These provide exciting new capabilities, such as studying the behavior 

of single layers of atoms on crystal surfaces, seeing the internal workings of materials as they deform, or seeing 

how materials behave inside living cells, among many others.

The race to create new materials produces a corresponding race to develop better ways to characterize 

them, and one of the directions that this race leads is toward ever-increasing sensitivity. If you design materials 

atom-by-atom, you need to characterize them at a corresponding level, but it is very hard to see a single atom 

if your specimen is shaking, even by just a tiny amount. In pursuit of ever-greater sensitivity, we are beginning 

the design of a new building that will house ultrasensitive characterization equipment in an environment that 

will have ultralow vibration, electrical interference and magnetic interference, allowing the most sensitive kind 

of analysis anywhere on earth. Funding for the planning phase for this sensitive instrument facility has been 

received from DOE, and we are hard at work identifying a suitable site, developing plans and learning from 

our sister labs, Argonne National Laboratory and Oak Ridge National Laboratory, which have both built similar 

facilities in the last few years.

From the Director

Alex King, Director

The race to create new materials produces a corresponding 

race to develop better ways to characterize them, and 

one of the directions that this race leads is 

toward ever-increasing sensitivity.

A
 Awards

Prozorov receives DOE Early Career Award

Tanya Prozorov, an Ames Laboratory scientist, will take an unprecedented look at how magnetic nanocrystals 

grow thanks to a DOE Office of Science Early Career Research award. Prozorov was one of just 65 researchers 

(21 from the national laboratories) selected from about 1,150 applications to the program, which is designed to 

bolster the nation’s scientific workforce by supporting “exceptional researchers during the crucial early years of their 

scientific careers when many scientists do their most formative work.”

Prozorov’s project, “Real-Time Studies of Nucleation, Growth and Development of Ferromagnetism in Individual 

Protein-Templated Magnetic Nanocrystals,” will focus on isolating individual bio-templated magnetic nanocrystals 

in an attempt to identify mechanisms that control how these crystals form and develop their magnetic properties. 

The award will provide a total of $2.5 million over a five-year period. (To read more about Prozorov’s research, turn 

to page 14.)

“I am excited about Tanya’s project because it promises to answer some really intriguing questions about materials at the nanoscale,” 

says Ames Laboratory Director Alex King. “Winning the funding against steep odds reflects DOE’s sense of the importance of the work, and 

confidence that she can overcome its challenges to get the job done.”

Tanya Prozorov

Soukoulis receives honorary degree

Ames Laboratory associate scientist and Iowa State University 

Distinguished Professor Costas Soukoulis received an honorary doctorate 

from Vrije Universiteit in Brussels, Belguim. Soukoulis was one of five 

scientists honored for accomplishments in their respective fields. He 

received the award during a ceremony held May 25 in Brussels.

Withers awarded Silvius-Wolansky 

Graduate Fellowship

Ames Laboratory industrial hygiene manager Jim 

Withers has been selected for the Silvius-Wolanksy 

Graduate Fellowship in the Iowa State University 

Department of Agricultural and Biosystems Engineering. 

Withers was selected for the fellowship based on his 

professional involvement in industrial 

hygiene/safety and his excellent 

dissertation research.

This fellowship was established to 

honor the work of G. Harold Silvius and 

William Wolansky, a long-time professor 

in industrial education and technology 

at Iowa State. Silvius and Wolansky 

were nationally recognized leaders 

committed to vocational education and 

training and international programs.

Jim Withers 

Ames Lab Public Affairs 

manager and education 

programs director Steve Karsjen 

has been invited to join the 

National Science Bowl Planning 

Committee. He will be involved 

in planning the event’s media/

public awareness activities.

Steve Karsjen

Thiel serves on ISU Presidential search committee

Ames Laboratory scientist and John Corbett Distinguished Professor of 

Chemistry Pat Thiel served as a member of the search committee tasked with 

finding the next president of Iowa State University. The 18-member committee met through much of the summer and narrowed the field to two finalists, 

with Steven Leath being named the 15th president of ISU on Sept. 27 by the 

Iowa Board of Regents. 

4 INQUIRY Issue 2 • 2011

Pat Thiel 

Karsjen appointed to National 

Science Bowl Planning Committee
INQUIRY Issue 2 • 2011 5

Ames Lab projects 

receive ARPA-E funding

The Ames Laboratory was selected for funding for two 

cutting-edge research projects by the Advanced Research 

Projects Agency-Energy (ARPA-E) program. 

The first of the two projects is for research to develop 

a new class of high-energy permanent magnets using the 

rare-earth element cerium. Cerium is four times more 

abundant than the rare-earth element neodymium, which 

is critical for today’s permanent magnets. The research will 

look at combining other metals with cerium to create a 

new, powerful magnet with high-temperature stability for 

electric vehicle motors. Partners in the project will also include General Motors, NovaTorque and Molycorp Minerals. 

The $2.2 million research project is for three years 

and will be led by Ames Laboratory senior metallurgist 

Bill McCallum, who says General Motors and NovaTorque 

will evaluate the material for traction motors in vehicles 

while Molycorp will provide the important materials supply chain and development path for commercialization of 

these materials. 

In the second project, Ames Laboratory scientists will 

team with Pacific Northwest National Laboratory on research to reduce dependence on critical materials like rare 

earths by developing a new alternative to rare-earth permanent magnets that use manganese. These manganese 

composite magnets hold the potential to double the magnetic strength of current rare-earth magnets while using 

raw materials that are inexpensive and abundant. 

Ames Laboratory senior chemist 

Ed Yeung has been selected to the 

2011 class of Fellows of the American 

Chemical Society. Yeung and the rest 

of 2011 ACS Fellows were honored 

at a special ceremony during the ACS 

National Meeting in Denver on Aug. 

29, 2011. The ACS Fellows Program 

recognizes members of ACS for 

“outstanding achievements in and 

contributions to Science, the Profession, 

and the Society.”

Chumbley elected Fellow of ASM International

Ames Laboratory scientist Scott Chumbley has been elected a 2011 Fellow of the American Society for Metals 

International. Chumbley was recognized at the ASM awards dinner during the ASM annual meeting on Oct. 18 in 

Columbus, Ohio.

ASM Fellowship is awarded for distinguished contributions in the field of materials science and engineering and 

provides a broad-based forum for technical and professional leaders to serve as advisors to the Society. Specifically, 

Chumbley was cited for “outstanding achievements in recruiting and mentoring of materials science and engineering 

students, and in the development of web-based SEM technology used by K-12 students worldwide.”

Paul Ness, senior research technician, 

was honored for 50 years of service to the 

Ames Laboratory. Ness was one of nearly 

30 Ames Lab employees recognized for 

their years of service completed in 2010 at 

an awards luncheon held Sept. 22.

Ness joins John Corbett and Karl 

Gschneidner as the only employees to 

reach their golden anniversary at the 

Lab. Ness received a gold watch bearing 

the Ames Lab logo and a certificate in 

recognition of his half century of service.

Ames Lab plays prominent role in 

superconductor workshop

Ames Laboratory played a prominent role in the 13th International Workshop 

on Vortex Matter in Superconductors, held in August in Chicago. Ames Lab was 

one of the sponsors, along with Argonne National Laboratory, the Materials Theory 

Institute of Argonne, the Institute for Theoretical Sciences of the University of Notre 

Dame, and the EFRC-Center for Emergent Superconductivity.

In addition, Ruslan Prozorov, Ames Lab senior physicist, served as a co-organizer 

for the workshop, and Ames Lab physicists Vladimir Kogan and John Clem were 

part of a special distinguished lecturers symposia and received special citations for 

their work. Clem also serves as a member of the workshop’s international advisory 

committee.

Kogan was recognized “for pioneering contributions to the vortex behavior of 

type II superconductors, especially the roles of anisotropy, non-locality, and multiple 

bands.” Clem was cited for his “seminal contributions to the phenomenological 

theory of vortices in superconductors including the concept of ‘pancake’ vortices in 

layered superconductors.”

Scott Chumbley

John Clem Vladimir Kogan Ruslan Prozorov

Ness honored for 50 years of service Yeung Selected as ACS Fellow

L-R: Alex King, Paul Ness Ed Yeung
education

6 INQUIRY Issue 2 • 2011

by steve karsjen

t would be hard to rival Ames Laboratory senior

scientist Mark Gordon’s success rate in attracting Science 

Undergraduate Laboratory Internship students to graduate 

school. Since the SULI program’s inception at Ames Lab, 

Gordon has been a program mentor four times. To his great credit, 

all three of the students he mentored those four years (one of 

his students participated in SULI twice) are now pursuing PhDs at 

Iowa State University and are working for him in the Applied Math 

and Computational Sciences program at Ames Lab. Anyone aware 

of Mark Gordon’s love of the New York Yankees would say team 

Gordon is batting a thousand.

 “Mark Gordon is a shining star when it comes to getting students 

to see the importance of going on to graduate school,” says Steve 

Karsjen, education programs director for the Ames Laboratory. “I 

think you’d be hard pressed to find many scientists throughout the 

entire DOE system who could equal Mark’s success rate in this area.”

Ames Laboratory’s SULI program started in 2005. That first 

year, the Lab hosted 10 undergraduates from colleges and 

universities around the country. Now just six years later, a total 

of 101 undergraduates have participated in the Lab’s SULI 

program, thanks in part to the great scientist/mentors they come 

in contact with at the Ames Lab and Iowa State. Sponsored by 

the Department of Energy’s Office of Science, the SULI program 

works to immerse undergraduate students in research settings at 

DOE’s national laboratories in an effort to encourage the students 

to pursue science, technology, engineering and mathematics, or 

STEM, careers. SULI students produce research reports, PowerPoint 

presentations and posters. Students conduct their research with an 

eye toward writing scientific papers worthy of being published in 

peer-reviewed journals. To date, Ames Laboratory SULI students 

have published 14 papers.

Team Gordon’s perfect batting average began in 2008 with the 

arrival of Caleb Carlin, then a junior majoring in physics with a minor 

in computational chemistry at Michigan Technological University. 

Upon graduation, Carlin enrolled in graduate school at ISU and 

began working in Gordon’s group. Carlin expects to graduate 

with his PhD in fall 2014. Ultimately, he says it was 

Gordon’s style and the overall style of the Gordon 

group that led him back to the Ames Laboratory 

and ISU following his SULI experience and 

college graduation. 

“The Gordon group is very open and 

welcoming, always happily answering any 

question no matter how mundane,” says 

Carlin. “In this Mark leads by example, 

personally making sure students stay on 

track. In short, he not only has a mastery of 

theoretical chemistry but also a mastery of 

guiding graduate students.” 

The SULI program itself, but to a larger extent 

his experience as a SULI student with Gordon 

SULI Success

I and his group in 2010, provided the impetus for the “hard right 

turn” Justin Conrad made in his post-graduation plans from the 

College of the Ozarks in Missouri. Prior to completing his first 

SULI internship, Conrad’s intention was to finish his undergraduate 

degree and pursue an entry-level job as a research chemist, 

possibly with the military. But that changed when in 2011 the 

SULI program provided him the option to participate a second year 

in an internship with Gordon and his group. 

“Prior to SULI, graduate school was just a word,” says Conrad. 

“Without Mark’s guidance, I would not be here.”

Getting students to Ames Laboratory and Iowa State for 

graduate school takes a coordinated approach that goes beyond 

simply analyzing a student’s background, according to Gordon. 

First, he says, students must be motivated, “wanting to learn, do 

cool stuff.” 

Second, mentors must be nurturing. “If mentors don’t nurture, 

then it’s a total turnoff for students,” Gordon says. 

Finally, comes the student’s “background.” Gordon contends all 

of his students are bright, which helps level the playing field in that 

area, so he says of the three, a student’s background comes in last. 

Gordon’s own background, however, did play a key role in 

guiding Colleen Bertoni, who participated in the SULI program in 

2009 as a graduating senior, back to Ames Laboratory and ISU. 

Following graduation from the University of Texas at Austin with a 

degree in chemistry, she decided to stay a fifth year in order to take 

additional coursework in computer science. All that time, she kept 

in contact with Gordon, who helped her see how the two degrees 

could mesh with one another, which, ultimately, helped her make 

the decision to come back to the Gordon group and ISU this fall. 

“Mark has been in the field a long time so he has a really good 

feel for what’s important in quantum chemistry and computational 

chemistry,” says Bertoni. “His knowledge of the field makes it very 

exciting. He helps you see all the connections.” 

As for the future of these students, well, it’s as different as 

you might expect. Carlin wants to become an analyst for the 

government. Bertoni likes the appeal of doing research at a DOE 

national lab. Conrad wants to first find a job in industry and then 

return to academia as a teacher. 

Whatever their ultimate decisions, Gordon feels he will have 

accomplished one of his main goals, which is to help maintain the 

flow of American students into science. 

“More and more of our international students are educated 

here and then go home to their home countries, so it’s important 

to educate young domestic students that science is a really exciting 

and viable career.” 

“This is what the SULI program allows,” he adds. “To have 

students come here and get their PhDs and get excited about 

science is really important to the future of our country.” 

 

Battin’ a Thousand in 
INQUIRY Issue 2 • 2011 7

Up to bat (left to right) are Justin Conrad (SULI ’10 and ’11), Mark Gordon 

(SULI mentor), Caleb Carlin (SULI ’08) and Colleen Bertoni (SULI ’09). 
8 INQUIRY Issue 2 • 2011 

o figure out why a material has particular

properties, scientists need to know far more than just 

the elemental chemical composition of that material. 

To really understand what makes a material “tick,” scientists need to probe the internal structure of the material to 

decipher just how the atoms and molecules within the material 

fit together, how they interact in various states and phases and 

how conditions such as temperature and magnetic field affect 

those interactions.

To characterize a material, scientists rely on a wide variety 

of analytical techniques. While individual characterization techniques are specialized to highlight different aspects of a material, 

they do share some things in common. Many techniques rely on 

the principle that atoms and molecules have a unique signature 

on the spectrum when subjected to electromagnetic radiation. 

The signature can manifest itself in different ways, but a simple 

example of this principle can be seen in a TV screen where a 

europium phosphor shows only the vivid red portion of the light 

spectrum when subjected to the broadcast signal.

Spectroscopy allows scientists to “see” what’s inside a material by viewing what happens to the electromagnetic radiation 

directed at the sample. Depending on the type of radiation used 

– running the gamut from radio waves, microwaves and light to 

X-rays and gamma rays – and its strength, scientists can measure how the energy is absorbed by the material, emitted by the 

material or scattered by the material.

In nuclear magnetic resonance (NMR) spectroscopy, for example, researchers use radio-frequency magnetic energy on a 

sample to measure the local magnetic fields generated by the 

nuclear spins. This provides detailed spectral information about 

the physical and chemical properties of the material, such as 

the distance between nuclei and their specific positions at a 

particular point in time.

C h aracteri z ation

T

Finding Out What Makes Materials “Tick”

by KERRY GIBSON

 A technique known as high angle annular dark field 

(HAADF) STEM can be used to create a high contrast image, 

such as the one of a co-block polymer on the left, to give a 

better view of the crystal structure of materials. At right is a 

TEM bright field image of the same co-block polymer, which 

provides a better view of the sample’s surface.

Ames Lab scientist Matt Kramer operates the Lab’s 

transmission electron microscope. Various equipment options 

allow scientists to probe different aspects of a material. 

In scanning mode, or scanning transmission electron 

microscopy (STEM), the electron beam is scanned back and 

forth across the sample. 
INQUIRY Issue 2 • 2011 9

CAM-2C’s capabilities include:

Scattering Sciences: X-ray, electron, and neutron

Microscopies: chemical imaging, gene expression imaging, differential interference contrast, field ion, scanning 

tunneling, atomic force and ultrafast stimulated emission 

depletion microscopies

Spectroscopies and Elemental Analysis: Auger, Raman, 

energy-dispersive X-ray spectroscopy, mass spectroscopy, 

angle-resolved photoemission spectroscopy, X-ray photoelectron microscopy, and solid-state NMR

Property Measurements: magnetization; susceptibility; 

transport; and thermodynamic quantities (e.g., heat capacities, enthalpies, magnetocalorics, thermopower, DTA, DSC 

and TGA) measured across a wide range of temperatures and 

applied magnetic fields (up to 14 Tesla)

“What sets Ames Laboratory apart from most materials research labs is the broad, yet integrated nature of the research, 

synthesis and characterization within our material discovery efforts,” Johnson says. “It involves numerous researchers, which 

are mirrored within the Lab’s four science cornerstones, and 

founded on our unique synthesis and processing of high-purity, bulk single crystals that may involve volatile elements.”

“With our `theoretical characterization’ capabilities (computational materials science and chemistry),” he adds, “we 

have an integrated feedback loop between theory and experiment that works very well, helping to speed up development 

and understanding.”

 

“Our characterization expertise 

and capabilities is a cornerstone of 

who we are at the Ames Laboratory.” 

Similarly, X-ray diffraction spectroscopy uses X-rays to probe 

the sample, and the interaction of the X-rays with the electrons 

in the materials results in the transference of energy from the 

X-rays. These “scattered” or defracted X-rays will have a different 

wavelength than the original beam. In highly ordered materials, 

these scattered rays will form a pattern that corresponds with 

the distribution of atoms within the material, providing keys to 

its crystal structure.

Some types of electron microscopy also rely on the material’s spectroscopic properties. In transmission electron microscopy, very thin samples are probed with an electron beam that 

passes through the material. As the beam passes through, some 

of the beam’s electrons are reflected. Different particles have a 

particular angle of reflection, so by using sensors to measure the 

angle of the reflected beam, scientists learn about the structure 

of the material. 

The Ames Laboratory’s strength in creating materials relies 

in large part on the expertise of its researchers in these various techniques to quantify particular aspects of a material. And 

the Lab’s highly collaborative atmosphere allows the snapshots 

gathered by these various characterization techniques to be 

drawn together to form a more complete picture.

“Our characterization expertise and capabilities are a cornerstone of who we are at the Ames Laboratory,” says Duane 

Johnson, Ames Lab’s chief research officer. “The Chemical and 

Advanced Materials Characterization Center, or CAM-2C (came 

to see), encompasses a broad range of techniques that directly 

benefit the DOE’s energy-sciences portfolio.”

Duane Johnson, Ames Lab’s chief research officer 
by KERRY GIBSON

hen DanNNY Shechtman first saw

the diffraction pattern with 10 points in 1982, 

he had no idea the ridicule he would face because of it, or that it would eventually lead to 

complete vindication in the form of the 2011 Nobel Prize in 

chemistry. As a scientist characterizing a new aluminum-manganese alloy, he simply knew he was seeing something unique 

that didn’t fit with the accepted rules for crystalline structure. And 

he believed what his eyes were seeing.

“I was working alone in the electron microscope lab (as a 

guest researcher at what was then the National Bureau of Standards) studying this new material and right away, it looked very 

strange to me,” Shechtman says. “So I took an electron diffraction and I counted 10 spots and said, ‘No, it cannot be!’”

“I counted again another way and it was still 10 spots,” he 

continues. “I thought, ‘10-fold symmetry ... this is an amazing thing! I must share it with somebody.’ 

So I went out in the corridor, but there 

was no one else around, so I went back 

and spent the rest of the day performing 

experiments.”

His initial thought was that the pattern he was seeing was the result of a 

phenomenon known as twinning, where 

two rows of atoms form a mirror image 

with a boundary in between them. But 

as he looked, he could find no evidence 

of twins. In rotating the crystal, he also 

discovered the material actually had an 

equally impossible five-fold rotational 

symmetry, not 10-fold as he first suspected, and he knew he was seeing 

something new and unexplained.

Shechtman’s discovery, which contradicted conventional wisdom, was discounted as “outrageous” and he was ridiculed by 

even his colleagues, including being dismissed from his research 

group. But he continued to study the material and in November 

1984, with support from physicist John Cahn, materials scientist 

Nobel Prize

W

10 INQUIRY Issue 2 • 2011 

Characterization

Anomaly Leads to

Danny Shechtman

“ ... I counted 

 10 spots and said, 

 ‘No, it cannot be!’”

Shechtman’s original lab notes
INQUIRY Issue 2 • 2011 11

Ian Blech, and crystallographer Denis Gratias, published his data 

in an article, “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry,” in Physical Review Letters. 

The article took Shechtman’s discovery, and criticism of it, 

to a whole new level. One of the harshest opponents was twotime Nobel Prize winner Linus Pauling.

“He was a highly respected scientist and the idol of the 

American Chemical Society and to his last day, he would stand 

on those platforms and declare, ‘Danny Shechtman is talking 

nonsense,” Shechtman recalls. “Pauling would often say, ‘There 

is no such thing as quasicrystals, only quasi-scientists.’”

However, Shechtman’s article also began to win over supporters who were able to replicate his results. Theoretical support for quasicrystals soon came about from an aperiodic mosaic developed by British mathematician Roger Penrose. By 1992, 

the International Union of Crystallography altered its definition 

of a crystal to “any solid having an essentially discrete diffraction 

diagram,” where it had previously suggested crystals had to be 

periodic in nature. 

Shechtman’s selection for the 2011 Nobel Prize in chemistry is the ultimate vindication for the years spent defending his 

discovery. His unwavering belief in his original findings holds 

an important lesson for anyone in the field of science or the 

broader scope of human endeavor. 

“If you’re a scientist and believe in your results, then fight for 

it ... fight for the truth,” he says. “Listen to others, but fight for 

what you believe in.”

Ames Laboratory senior scientist Pat Thiel, 

who was instrumental in bringing Shechtman 

to Ames Lab and Iowa State University, marvels at Shechtman’s tenacity and his ability to 

stay cordial and respectful with even his most 

vocal critics.

“The stories of his life and career have 

been inspirational to me, especially the controversy with Linus Pauling and the fact that 

they remained on cordial terms even as they battled professionally,” says Thiel. “In fact they met several times for dinner at 

conferences, and Danny once made a special visit to Linus to try 

to convince him about quasicrystals.”

“Most people would have become bitter and incensed,” 

Thiel continues, “but Danny didn’t and in fact, he did not even 

take the controversy as a personal affront. To remain on civil 

and respectful terms with people, even in the face of strong 

disagreements, is one of my professional aspirations and also 

one of the most remarkable aspects of Danny’s achievement.”

For Paul Canfield, Ames Lab senior 

physicist, Shechtman’s discovery has been 

an ongoing subject of study throughout 

Canfield’s career.

“Danny’s discovery was profound,” Canfield says. “Quasicrystals offered a mysterious 

waystation between crystalline and amorphous. Just how this new form of order affects the physical properties of quasicrystals is 

something I keep coming back to over the decades.”

Canfield’s first publication as a graduate student at UCLA 

was the measurement of meltspun quasicrystalline ribbons. At 

Ames Lab, he was able to grow some of the first faceted singlegrain, rare-earth-magnesium-zinc quasicrystals, a perfect blend 

of Ames Lab’s expertise in rare earths and quasicrystals. 

“With (Ames Lab senior physicist) Alan Goldman we were 

able to determine that rare earths, ordered in a quasicrystal, act 

in a manner similar to a glass, but a highly ordered one,” he says. 

“With our discovery that solution growth was an excellent way 

to grow these complex materials, we expanded the number of 

systems we studied and actually taught the world how to grow 

these compounds.” 

“It is my firm belief that if we look carefully enough and grow 

carefully enough, there will be many examples of quasicrystals 

lurking in binary and ternary phase diagrams,” Canfield concludes. “The real big remaining question is to understand why 

a material forms a quasicrystal rather than a crystalline phase.”

Alan Goldman agrees that Shechtman’s 

findings have ultimately changed the way researchers think about the composition of matter.

“Danny’s discovery really opened a new 

frontier in materials research and certainly 

had a very strong impact on my own career,” 

Goldman says. “Very soon after his discovery, I 

began to study the structure and properties of 

quasicrystals at Brookhaven National Laboratory. When I came to Ames in 1988, I continued that work with 

other Ames Lab scientists such as Pat Thiel, Paul Canfield, Matt 

Kramer, Bill McCallum and Tom Lograsso,” he continues, “and I 

can only say that it has been a ‘fantastic journey’ that epitomizes 

the Ames Lab’s interdisciplinary approach to science.”

 

far left: A holmium-magnesium-zinc (Ho-Mg-Zn) quasicrystal, 

grown by Ames Laboratory senior physicist Paul Canfield, 

that clearly shows five-fold (pentagonal) symmetry.

left: An X-ray diffraction image captured by Alan Goldman 

that shows the “10-spots” that Shechtman first noticed 

through his transmission electron microscope.
12 INQUIRY Issue 2 • 2011 

evelopment of biofuels hinges on the ability 

to convert lignocellulose, the “woody” cell membrane 

that comprises most plant material, into something 

that’s useable as fuel. One method is to use enzymes 

to break down the cellulose into sugars, which can then be converted into ethanol through fermentation and distillation.

Because different plants have different cell-wall structures 

and compositions, scientists need to understand those differences and how efficiently enzymes are able to break the lignocellulose into simple sugars. To do this, Ames Laboratory 

scientist Emily Smith uses a characterization tool called Raman 

spectroscopy, which is ideally suited to working with such materials.

“This method has several advantages over alternative analytical techniques,” Smith explains. “First, analysis requires very 

little material so you can take small samples from a growing 

plant over time with little damage to the plant.” The technique 

is also high-throughput. Because only very small samples are 

needed and little time is required to prepare samples, multiple 

samples can be analyzed quickly.

The basic Raman technique used by Smith, who is also an 

Iowa State University assistant professor of chemistry, employs 

an optical microscope, and specimens are illuminated with a 

laser beam. As the laser light hits the sample, some of the 

light is scattered.  By analyzing the scattered light with a spectrometer, Smith can easily and quickly determine the chemical 

makeup of the plant material.

“Raman spectroscopy provides chemical signatures of 

what’s in your sample,” Smith says. “We can focus on the 

signature of the particular species we’re interested in, for example lignin or cellulose.”

Because lignin binds the cellulosic polymers together, the higher the lignin content 

of the cell wall, the harder it is to access the 

cellulose. For some biofuel applications, plants 

with a higher cellulose-to-lignin content are 

more ideal.

Smith’s group is also using Raman spectroscopy to measure the enzymatic reactions 

used to break down the cellulosic polymers 

into sugars.

“Because the enzymes used can be expensive, it’s important to determine what conditions are optimum to produce the highest 

yield,” Smith says. 

Besides the type of plant material used, 

variables include the maturity of the plant material, the size of the pieces being processed, 

pretreatment of the material, and the type and 

amount of enzyme used.

Also being studied is a hydrolysis process that uses enzymes 

attached to silica nanoparticles. This allows the nanoparticles 

and their attached enzymes to be recycled. It also increases 

the yield of ethanol when saccharification and fermentation 

reactions are performed simultaneously. 

Smith’s work has also focused on developing new instrumentation and uses for it. She is currently developing a different type of Raman technique known as scanning angle, total 

internal reflection Raman microscopy.

“Basically, it allows us to control the angle that the laser is 

directed on the sample,” Smith says. “By changing the incident angle, we hope to be able to develop a 3D image of the 

sample’s chemical content.” 

Motorized controls allow the incident angle of the laser to 

range from 25.5 degrees to 75.5 degrees with a .05 degree 

angle resolution, giving researchers the capability to study the 

materials with 5 nanometer spatial resolution.

At an even more fundamental level, Smith’s group is looking at how the spectral signal is generated and how to enhance 

the signal strength.

“When I first arrived, I wasn’t expecting to do anything related to biofuels, but there is such an interest in them and a 

wealth of expertise here and at Iowa State that it’s really taken 

off,” Smith said. “As we’ve worked on that, our understanding 

of these techniques has grown and it’s brought up all kinds of 

new research projects for us to work on.” 

Raman spectroscopy shines a light on biofuels processing

D

Laser-guided Discovery

by KERRY GIBSON

Above: A schematic for the scanning angle total internal reflection 

microscope that Emily Smith displays on the opposite page.
“This method has several advantages over other 

analytical techniques,” Smith explains. “First, 

analysis requires very little material so you can 

take small samples from a growing plant over 

time without damaging the plant.”

INQUIRY Issue 2 • 2011 13
14 INQUIRY Issue 2 • 2011 

Tanya Prozorov demonstrates working with biological samples using existing equipment. Prozorov is awaiting arrival of a 

new continuous flow liquid cell holder for the Lab’s transmission electron microscope that will allow her to study how magnetic 

nanocrystals, similar to those shown in the micrograph at the right, form.

mes Laboratory scientist Tanya Prozorov

is clearly enthusiastic when she talks about her research. She has trouble suppressing a smile as she 

excitedly details the project that will take her into 

uncharted territory. 

This “expedition,” however, won’t take her and her yet-to-benamed research team to some exotic location. The new territory 

will be trying to watch biomagnetic crystals as they form using 

a custom-built sample holder for the Lab’s Technai transmission electron microscope. The work is being funded through a 

five-year, $2.5 million Department of Energy Early Career Award 

which Prozorov was awarded earlier this year.

Prozorov’s project, “Real-Time Studies of Nucleation, Growth 

and Development of Ferromagnetism in Individual Protein-Templated Magnetic Nanocrystals,” will focus on isolating individual 

biotemplated magnetic nanocrystals in an attempt to identify 

the mechanisms that control how these crystals form and develop their magnetic properties. 

“With the majority of current characterization techniques, 

what you see is a static picture – a snapshot – of multiple 

nanocrystals,” Prozorov says. “These particles interact with each 

other, and it masks what’s really taking place.” 

“Also, we normally observe them after they’ve formed,” she 

continues. “I want to try to isolate and view individual particles 

as they grow, in situ, to see what’s taking place. There’s nothing 

like actually seeing it to help you understand how they form. 

And understanding this will ultimately allow controlling the 

emergent magnetism.”

Building her expertise in specialized electron microscopy 

techniques is the first step, according to Prozorov, who describes 

herself as “just a materials chemist with a passion for electron 

microscopy.” For example, to study growing, bio-inspired samples requires that they be suspended in liquid, which presents 

a particular set of problems.

“It takes a specialized piece of equipment – a continuous 

flow liquid cell TEM (transmission electron microscope) holder 

– to be able to view the nanocrystal formation in liquid,” she 

says. Additionally, a “molecular printer” called a Nano Enabler 

is necessary to dispense the requisite nano-scale quantities of 

the biological templating material. Cryo-electron microscopy 

techniques will be used to literally freeze the particles in various 

stages of development so their images can be captured.

Prozorov will collaborate with Ames Lab scientist and electron microscopy expert Matt Kramer and his group. She’ll also 

continue to work closely with faculty scientist Surya Mallapragada, whose research group focuses on the bio-inspired magnetic 

nanocrystals that led to Prozorov’s proposal for the Early Career 

Award program.

Uncharted Territory:

A

Watching Nanocrystals Grow

“With the majority of current characterization techniques, what 

you see is a static picture – a snapshot – of multiple nanocrystals,”

Prozorov says. “These particles interact with each other, and it masks 

what’s really taking place.”

by KERRY GIBSON
INQUIRY Issue 2 • 2011 15

new material’s journey from discovery to

ultimately improving everyday products often starts 

with scientists studying the material’s microscopic 

properties through neutron and X-ray scattering.

“The first thing that we need to know about a new material is its structure and how it behaves under external stimuli,” 

says Alan Goldman, Ames Laboratory physicist and member of 

the Lab’s scattering research group. “Minor changes in material 

composition, made to either reduce costs or weight or to enhance efficiency, can represent significant savings over current 

materials. So, the structure and behavior of materials is critical 

for understanding how to create the next generation of materials and products.”

Take, for instance, the new type of iron-arsenic superconductor discovered several years ago. Scientists hope iron-arsenides 

may prove useful in applications, such as in high-strength superconducting magnets, but first the materials’ properties must be 

mapped out. In particular, Ames Laboratory’s scattering group 

— which includes Goldman, Rob McQueeney, David Vaknin and 

Andreas Kreyssig, all Ames Laboratory physicists, along with 

several post-doctoral researchers and graduate students — was 

interested in the magnetic structure of a type of iron-arsenide 

where a small percentage of the iron was replaced with cobalt 

in a process called “doping.”

The team studied the material using neutron scattering, 

which is best suited for studying magnetic structure as neutrons 

are sensitive to the magnetism in materials. In neutron scattering, a beam of neutrons is generated in a nuclear reactor or 

an accelerator-based spallation source and, using specialized 

instrumentation, is aimed at a sample of material. The neutrons 

in the beam encounter nuclei and atomic magnetic moments 

in the sample and bounce off. The way the neutrons “scatter” 

from a material gives scientists information about where the 

nuclei and magnetic moments are located and how they are 

moving.

In studying cobalt-doped iron-arsenides, the Ames Laboratory scattering group used finely-tuned samples synthesized at 

Ames Lab by fellow physicist Paul Canfield. The scattering research group was able to gather enough information about the 

magnetic order and superconducting phase to map out a phase 

diagram of the material.

“Turns out this cobalt-doped iron-arsenide is an interesting 

case where the magnetic order and superconductivity can coexist in a finite doping range,” says Rob McQueeney. “Our group 

was the first to discover that.”

For other scientific questions, like studies of rare-earth materials, one of Ames Laboratory’s specialties, X-ray resonant 

magnetic scattering is better suited. In X-ray resonant magnetic 

scattering, a material sample is exposed to a beam of finely 

tuned X-ray energy that is specific to the probed element. The 

X-rays scatter from electrons in the material, revealing information about materials’ magnetic structure.

“This technique is only possible at high-brilliance X-ray 

sources like the Advanced Photon Source at Argonne National 

Laboratory,” says Goldman. “In fact, we spend a lot of time traveling because our research requires ‘beam time’ at the major 

scientific facilities in the United States and around the world.”

The scattering group also uses various scattering techniques 

in research on bio-inspired materials. It tries to understand 

the mechanisms by which organisms build functioning 

minerals such as bones, teeth and shells, and magnetic 

nanocrystals. The objective of the group is to employ similar 

biomineralization processes to design novel materials for 

various applications.

“In all these projects, we use the scattering technique that 

is appropriate to the scientific question, and often we use both 

neutron scattering and X-ray resonant magnetic scattering because the data gathered from each is complementary,” says 

Andreas Kreyssig. “I think that is a strength of our team here at 

Ames Laboratory.”

 “From sample growth and the variety of very detailed kinds 

of scattering techniques we use, to theoretical interpretation, 

we have it all here at the Ames Laboratory,” adds McQueeney. 

“That’s what makes it possible for us to make such an impact 

in this field.”

A

Scattering at the Ames Laboratory

The scattering research group at Ames Laboratory uses X-ray 

resonant magnetic scattering, along with other types of scattering, to map out the phase diagrams for new materials. Shown 

here is the phase diagram for a cobalt-doped iron arsenide. 

The scattering team’s research indicates that in this material, 

magnetic order (blue area) and superconductivity (yellow area) 

can coexist (green area), which is unusual.

by breehan gerleman lucchesi
16 INQUIRY Issue 2 • 2011

he answers to big questions – how to create

green fuels or how to cure deadly diseases – may have 

their answers in tiny motions in living cells. To understand 

these small movements, Ning Fang, associate scientist, is 

using optical microscopy to see how nanoparticles are manipulated by “nanomachines” in cells.

In living cells, numerous biological nanomachines perform 

various functions. But according to Fang, scientists have only a 

limited understanding of how these nanomachines work, especially in cellular environments. And because the malfunction of 

any of these nanomachines can lead to diseases, there is a great 

need for new techniques to help investigate the composition, 

dynamics and working mechanisms of these nanomachines. 

Nanomachines are also very efficient at converting chemical or 

other energy into motion, so understanding them may give scientists ideas for how to build efficient green-energy technology 

at the micro- or macroscale.

To understand how these nanomachines work, scientists examine how nanoparticles move with various types of motion induced by nanomachines that are essential to their function. 

Translational motion, or movement in which the position of 

an object is changed, can be tracked through a variety of current 

techniques. However, rotational motion, which is as important 

and fundamental as translational motion, was largely unknown 

due to technical limitations.

Previous techniques, such as particle-tracking or single-molecule fluorescence polarization, only allowed rotational movement to be resolved in simplified, controlled in vitro systems.

In its research, Fang’s group has gone beyond studying motions 

in the in vitro environment to imaging rotational movement in 

the in vivo, or live cell, environment.

To do this, the group relies upon the use of gold nanorods, 

which are only 25 by 73 nanometers in size (a well-packed 

bundle of 1000 nanorods has the same diameter as a human 

hair). In live cells, these nontoxic nanorods scatter light differently depending upon their orientation. Using a technique 

called differential interference contrast microscopy, or DIC, 

Fang’s team can capture both the orientation and the position 

of the gold nanorods in addition to the optical image of the 

cell and, thus, reveal a particle’s 6D (three spatial coordinates, 

two orientation angles and time) movement within living cells. 

 “This new technique opens doors to understanding the 

working mechanism of living nanomachines by revealing their 

complex internal motions,” says Fang. “Studying rotational motions at the nanometer scale inside a living cell is just something that has never been done before.” 

He added that understanding this rotational motion is important in the fight against diseases, such as Alzheimer’s, because it can help scientists better understand how neurons are 

impacted by the environment.

Fang’s research group is also developing another type of 

DIC microscopy that generates a high-contrast, high-resolution 

view of materials that would be invisible under conventional 

light microscopes, so Fang and his colleagues can visualize the 

composition of block copolymers.

“DIC uses a special principle based on interference so we 

can see inside these polymers down to about a domain of a few 

tens of nanometers or even smaller,” Fang says. “The polymers 

appear to have different patterns of nanostructures, and we are 

now hoping that this understanding will lead to applications in 

clean energy.”

In addition, Fang’s team is working in the area of super-resolution fluorescence imaging, with the goal of visualizing ever finer 

details of materials.

“The overall goal is to break the diffraction limit of light,” says 

Fang. “For example, we want to be able to distinguish between 

two fluorescent molecules that are so close to each other that 

they previously would have appeared as one.”

His team’s technique, called 3D super-resolution fluorescence microscopy, has the added benefit of automation.

“Compared to others’ systems, we can control most parts 

of the microscope by computer, so the computer automatically 

calibrates and carries out the scan,” says Fang. “This means the 

system is very convenient for end users, and, more importantly, 

we can better reproduce the results of our imaging process.”

In all these types of imaging, Fang’s group is working to improve the ability to manipulate samples during imaging.

“We need better control of the sample so that we can pinpoint when and how we introduce external triggers to samples,” 

explains Fang. “For instance, we are studying the enzymatic reaction for breaking down cell walls to examine how to best make 

biofuel. That type of experiment requires introducing a reagent 

to the sample to start the reaction.”

The controls are provided by a cleverly designed microchannel network, and Fang and his colleagues have introduced the 

first type that can work with high-fidelity optical imaging.

Overall, Fang’s goal is to improve on the complete platform 

of optical imaging. 

“We seek to improve localization, that is, we want to see a 

particle’s location with nanometer precision, and we want to improve resolution, so we can identify two close particles as individuals,” says Fang. “We also want to be able to track particles’ 

movements, and we want to be able to manipulate the samples.”

“The complete platform of imaging, combined with collaborating with others at Ames Laboratory with different techniques, 

is one advantage we have here at Ames Lab,” adds Fang. “We 

can use all of our techniques to examine one material. We gain 

more basic understanding of the material that may someday 

lead to important applications.”

T

Unlocking the Power of Nanomachines

Ning Fang is using optical microscopy to study the mechanisms 

of biological nanomachines. Here, a gold nanorod is attached 

to a microtubule. Tracking the movement of the nanorod reveals 

the rotation of the microtubule.

by breehan gerleman lucchesi
left: Transmission electron microscopy image of gold nanoparticles. Right: Differential interference contrast images of two 25 by 

73 nanometer gold nanorods positioned at different orientations. The periodic changes of bright and dark intensities allows the 

nanorods’ orientation to be determined with high precision. Bottom: (from left) Ning Fang, Wei Sun and Gufeng Wang.

“This new technique opens doors to understanding 

the working mechanism of living nanomachines by 

 revealing their complex internal motions ...”

INQUIRY Issue 2 • 2011 17
18 INQUIRY Issue 2 • 2011

ransistors and information storage devices

are getting smaller and smaller. But, to go as small as the 

nanoscale, scientists must understand how just a few 

atoms of metals behave when deposited on a surface. 

Physicists at the Ames Laboratory are studying the interaction 

of materials that are promising for use in nanoscale electronics: graphene and different types of metals. The team has discovered that the rare-earth metals dysprosium and gadolinium 

react strongly with graphene, while lead does not. 

Michael Tringides, an Ames Laboratory senior physicist, and 

colleagues Myron Hupalo, an Ames Laboratory scientist, and 

Steven Binz, a graduate student in physics, deposited a few 

atoms of lead or rare-earth metals on the surface of graphene, 

a one-atom thick layer of carbon. In a process called self assembly, the atoms move on their own and form “islands” or smooth 

films on graphene. Tringides and the team then used scanning 

tunneling microscopy to study the islands’ geometry.

STM creates realistic images of nanoscale surfaces in fine 

detail. In the STM, scientists mount a sample and deposit atoms 

to make nano-islands. Then they use a tiny needle to approach 

the sample surface. The needle gets close to the sample, as 

close as one atom-width away, but doesn’t touch the surface, 

leaving a small gap. 

To make measurements, the STM relies on two concepts in 

quantum mechanics: electrons are both a particle and a wave; 

and the electrons, acting as waves, “tunnel” through the gap 

between the sample and the needle tip.

“Tunneling allows current created by the electrons to move 

from the sample to the STM needle,” says Tringides. “The 

amount of current is dependent on how far the needle is from 

the sample, so the STM measures this current and uses it to 

keep the needle the same distance away from the sample.”

As the needle scans the surface, it encounters dips and 

peaks -- where the atoms are -- but maintains an equal gap 

above the sample. The STM then traces the path of the needle 

up and down to create an image of what the sample surface 

looks like, representing the size and height of any structures on 

the surface.

STM images are complemented with data gathered with a 

different instrument, using scattering of low-energy electrons. 

In this technique, a beam of electrons is focused on a sample 

that has islands on a smooth surface. Electrons bounce off the 

tops of the islands and the substrate. Because the electrons 

travel different distances, they form interference bands, giving 

scientists information about the nano-islands’ height and size.

Tringides and his team also collaborate with other research 

groups that use additional types of characterization techniques, 

such as X-ray surface scattering, which is able to examine the 

deeper structures of the islands close to the substrate, and lowenergy electron microscopy, which is able to capture real-time 

movies of how atoms move on surfaces.

In its research into rare-earth islands on graphene, the team 

used STM to help understand how the atoms diffuse, particularly how quickly.

T

A Nanosized Look at the Bonds Between

Rare-earth Metals and Graphene

by breehan gerleman lucchesi

These micrographs show dendritic “island” growth of gadolinium on graphene at room temperature. This type of growth indicates a 

strong bond between gadolinium and graphene.
INQUIRY Issue 2 • 2011 19

“In this case, the lead atoms moved quickly when we cooled 

them down, while the dysprosium moved slowly, even after we 

heated them up,” says Tringides.

How fast or slow the atoms move and form islands offers 

insight into how each material interacts, or shares electrons, 

with the graphene. 

“If the atoms move fast, it means you do not have strong interaction,” Tringides says. “It’s like hockey pucks skimming along 

on an ice rink. There’s little interaction.”

In the case of dysprosium, the slow-moving atoms suggest 

that the metal reacts strongly with graphene. Gadolinium has 

an even stronger interaction. The interaction is significant because harnessing the potential of graphene in electronics will 

require attaching metals to graphene to conduct electricity.

“The hope is that graphene can be used for super-fast transistors,” says Tringides. “Our work is relevant to this because 

when you put metal on graphene, you want to have very good 

contact, so the electrical resistance is low.”

Tringides also says that the rare-earth islands on graphene 

are tiny magnets.

“It turned out that these islands were good nanomagnets on 

graphene,” Tringides explains. “You have a very high density of 

nanomagnets. Iron also has a similar high island density. This 

may be useful in the future for using metals on graphene in 

computer memory.”

Ames Laboratory theoretical physicists C.Z. Wang and KaiMing Ho collaborated on the research, using calculations to 

confirm the experimental results about the bonds between graphene and the metals studied. 

“These findings are interesting for both the fundamental 

physics and the potential usefulness,” says Tringides. “Whenever you say ‘nano,’ you can make a lot of something in a 

small size. And that might be very beneficial for something like 

magnetic computer memory.”

Tringides and his team are also working to understand several other questions about nanosized structures. They are examining the fast and correlated movement of lead atoms when 

they are placed on silicon at temperatures well below room 

temperature. At such low temperature the motion should be 

slow and random, but for a still mysterious reason the motion 

is extremely fast and the atoms “slide” together like a liquid. 

The team is also studying how magnesium nano-islands and 

films can adsorb hydrogen at the nanoscale, which may have 

implications for macroscale hydrogen storage technologies.

Three different types of materials yield three 

different types of island growth: (above, 

top row) lead on a lead surface; (above, 

bottom row) indium on lead surface; 

and (right) magnesium on lead surface.
2011ISSUE 2

Ames Laboratory

111 Technical and Administrative Services Facility

Ames, Iowa 50011-3020

515-294-9557

www.ameslab.gov

ISSUE 2