Search query: Strain-dependent optical properties of the novel monolayer

Related papers:

abstract: We studied the structural, electronic, and optical characters of SiS2, a new type of group IV VI two dimensional semiconductor, in this article. We focused on monolayer SiS2 and its characteristic changes when different strains are applied on it. Results reveal that the monolayer SiS2 is dynamically stable when no strain is applied. In terms of electronic properties, it remains a semiconductor under applied strain within the range from 10% to 10% Besides, its indirect band gap is altered regularly after applying a strain, whereas different strains lead to various changing trends. As for its optical properties, it exhibits remarkable transparency for infrared and most visible light. Its main absorption and reflection regions lie in the blue and ultraviolet areas. The applied uniaxial strain causes its different optical properties along the armchair direction and zigzag direction. Moreover, the tensile strain could tune its optical properties more effectively than the compressive strain. When different strains are applied, the major changes are in blue and ultraviolet regions, but only minor changes can be found in infrared and visible regions. So its optical properties reveal good stability in infrared and visible regions. Therefore, SiS2 has a promising prospect in nano electronic and nano photoelectric devices.
author_names: Qingyuan Chen

Ming-yang Liu

Chao Cao

Yao He
title: Strain dependent optical properties of the novel monolayer group IV dichalcogenides SiS2 semiconductor: a first principles study
venue: Nanotechnology
year: 2021

abstract: Motivated by the recent synthesis of layered hexagonal aluminum nitride $h$ AlN) we investigate its layer and strain dependent electronic and optical properties by using first principles methods. Monolayer $h$ AlN is a wide gap semiconductor, which makes it interesting especially for usage in optoelectronic applications. The optical spectra of 1 2 3 and 4 layered $h$ AlN indicate that the prominent absorption takes place outside the visible light regime. Within the ultraviolet range, absorption intensities increase with the number of layers, approaching the bulk case. On the other hand, the applied tensile strain gradually redshifts the optical spectra. The many body effects lead to a blueshift of the optical spectra, while exciton binding is also observed for 2D $h$ AlN. The possibility of tuning the optoelectronic properties via thickness and/or strain opens doors to novel technological applications of this promising material.
author_names: D Kecik

Cihan Bacaksiz

R T Senger

Engin Durgun
title: Layer and strain dependent optoelectronic properties of hexagonal AlN
year: 2015

abstract: The search for new two dimensional (2D) materials with novel optical and electronic properties is always desirable for material development. Herein, we report a comprehensive theoretical prediction of 2D SiC compounds with different stoichiometries from C rich to Si rich. In addition to the previously known hexagonal SiC sheet, we identified two types of hitherto unknown structural motifs with distinctive bonding features. The first type of 2D SiC monolayer, including t SiC and t Si2C sheet, can be described by tetragonal lattice. Among them, t SiC monolayer sheet is featured by each carbon atom binding with four neighboring silicon atoms in almost the same plane, constituting a quasi planar four coordinated rectangular moiety. More interestingly, our calculations demonstrate that this structure exhibits a strain dependent insulator semimetal transition, suggesting promising applications in strain dependent optoelectronic sensors. The second type of 2D SiC sheet is featured by silagraphyne with acetylenic linkages CC Silagraphyne shows both high pore sizes and Poisson's ratio. These properties make it a potentially important material for applications in separation membranes and catalysis. Moreover, one of the proposed structures, g silagraphyne, is a direct band gap semiconductor with a bandgap of 0.89 eV, which has a strong absorption peak in the visible light region, giving a promising application in ultra thin transistors, optical sensor devices and solar cell devices.
author_names: Dong Fan

Shaohua Lu

Yundong Guo

Xiaojun Hu
title: Novel bonding patterns and optoelectronic properties of the two dimensional SixCy monolayers
year: 2016

abstract: Since their discovery, single layer semiconducting transition metal dichalcogenides have attracted much attention, thanks to their outstanding optical and mechanical properties. Strain engineering in these two dimensional materials aims to tune their bandgap energy and to modify their optoelectronic properties by the application of external strain. In this paper, we demonstrate that biaxial strain, both tensile and compressive, can be applied and released in a timescale of a few seconds in a reproducible way on transition metal dichalcogenides monolayers deposited on polymeric substrates. We can control the amount of biaxial strain applied by letting the substrate expand or compress. To do this, we change the substrate temperature and choose materials with a large thermal expansion coefficient. After the investigation of the substrate dependent strain transfer, we performed micro differential spectroscopy of four transition metal dichalcogenides monolayers (MoS2, MoSe2, WS2, WSe2) under the application of biaxial strain and measured their optical properties. For tensile strain, we observe a redshift of the bandgap that reaches a value as large as 95 meV/ in the case of single layer WS2 deposited on polypropylene. The observed bandgap shifts as a function of substrate extension/compression follow the order MoSe2 MoS2 WSe2 WS2. Theoretical calculations of these four materials under biaxial strain predict the same trend for the material dependent rates of the shift and reproduce well the features observed in the measured reflectance spectra.Strain engineering: Tuning the bandgap of 2D materialsThe bandgap of two dimensional semiconducting materials can be easily tuned in real time by stretching or compressing them. An international team of researcher led by Dr. Andres Castellanos Gomez at IMDEA Nanoscience, Spain, studied the optical properties of single atom thick two dimensional semiconductors under the application of tensile or compressive biaxial strain. In order to apply the strain the researchers exploited the thermal expansion or compression of the different substrates carrying the atomically thin materials and then compared their results to atomistic simulations. This strain method can be applied in a fast and reversible way and it leads to large changes in the band structure of these semiconducting materials. Research into strain engineering two dimensional materials may help us in fabricating novel devices like color changing light emitters or novel and more efficient solar cells.
author_names: Riccardo Frisenda

Matthias Druppel

Robert Schmidt

Steffen Michaelis de Vasconcellos

David Perez De Lara

Rudolf Bratschitsch

Michael Rohlfing

Andres Castellanos-Gomez
title: Biaxial strain tuning of the optical properties of single layer transition metal dichalcogenides
venue: npj 2D Materials and Applications
year: 2017

abstract: We describe a facile technique based on polymer encapsulation to apply several percent controllable strains to monolayer and few layer Transition Metal Dichalcogenides (TMDs) We use this technique to study the lattice response to strain via polarized Raman spectroscopy in monolayer WSe2 and WS2. The application of strain causes mode dependent redshifts, with larger shift rates observed for in plane modes. We observe a splitting of the degeneracy of the in plane E modes in both materials and measure the Gruneisen parameters. At large strain, we observe that the reduction of crystal symmetry can lead to a change in the polarization response of the A mode in WS2. While both WSe2 and WS2 exhibit similar qualitative changes in the phonon structure with strain, we observe much larger changes in mode positions and intensities with strain in WS2. These differences can be explained simply by the degree of iconicity of the metal chalcogen bond. One of the iconic characteristics of monolayer 2D materials is their incredible stretchability which allows them to be subjected to several percent strain before yielding [1] The application of moderate ~1% strains is expected to change the anharmonicity of interatomic potentials [2, 3] phonon frequencies [4, 5] and effective masses [6, 7] At larger strains, topological electronic[8] [9] and semiconductor metal structural phase changes have been predicted [10 13] Important technological applications such as piezoelectricity can be explored by the application of systematic strain [14, 15] One of the chief problems in achieving reproducible strain is the intrinsic nature of 2D materials as single layer sheets they need to be held to a flexible substrate which is then stretched or compressed. Previous experiments [16 19] have used flexible polymers as substrates and metal or polymer caps in order to constrain the 2D material. Using these techniques, approximate strains up to 4% have been reported so far in the literature, but independent verification of the applied strain has been lacking. Achieving large reproducible strains in engineered geometries will allow us to probe these exciting properties of individual 2D materials and their heterostructures [4, 17, 20 26] In this work, we develop a new strain platform to apply large range accurate uniaxial tensile strains on monolayer and fewlayer materials. One of our chief innovations is the development of a novel polymer based encapsulation method to enable the application of large strain to 2D materials. Here, we apply this technique to study the strain dependent properties of monolayer WSe2 and WS2 grown by Chemical Vapor Deposition (CVD) on SiO2/Si substrates [27 29] We use cellulose acetate butyrate (CAB) to lift the monolayers from the SiO2/Si substrates and transfer to polycarbonate substrates. The two polymers are then bonded to produce encapsulated monolayers and multilayers. The key to achieving good bonding is perfect control over the temperature, time and pressure during the bonding process. Additionally, polymer layers that are in the amorphous phase cause nonlinear strain deflection behavior which is not desirable in our experiments. To resolve this issue, we crystallize the polymer stacks by annealing near the glass transition temperature followed by slow cooling. The crystallized polymers are fully flexible, elastic and springy substrates as shown in Fig. 1(a) After all of our processing steps, we find that the polymer stacks enter into the plastic regime at 7% strain. We find that strains up to this value are perfectly transferred to the encapsulated 2D material as described below. Our strain method adopts the extra neutral axis bending technique Fig. 1(b) in which areas above the neutral axis undergo tensile strain while those below the axis experience compressive strain. In our method, we use a screw driven vertical translation stage to apply strain to the polymer stacks. We solve the Euler Bernoulli equation for our geometry in order to achieve an accurate relation between the vertical displacement d of the translation stage and the strain e of the 2D material. For a fully isotropic, linear and elastic material, the strain displacement relation is derived as: e 3td a(3b 2a) where t is the substrate thickness, b and a are center support and cantilever lengths respectively. In our experiments, the use of a fine adjustment screw gives us a resolution of 0.05% strain for 0.5 mm substrates, with essentially no limit to the maximum strain that can be applied. More details are provided in the Supplemental Material. Shown in Fig. 1(c) is an optical image of triangular flakes of WSe2 encapsulated by this process. We adjust the CVD process to produce triangular flakes in order to easily identify the crystallographic directions of the grown monolayers. Since the strains achievable in our experiments are large, we can directly verify from optical measurements that the strain being applied to 2D layer is the calculated value. This is illustrated in Fig. 1(d) Each of these images is obtained by overlaying two images, one at zero strain and one at a fixed value of strain (4.2% and 6.5% respectively) Only the edges of the triangles are shown in the images, which are lined up to be at the same vertical height at the top vertex of the triangle. We can directly see by inspection that the length of the triangle along the strain direction is larger when strained as one expects. A pixel height measurement of the edge detected images gives us a direct experimental measure of the applied strain, which can be compared to the calculated strain based on the screw displacement. It is found that the two measurements match within 0.1% absolute strain. Thus, our technique allows for the application of uniform, highly repeatable and independently measurable strain on TMD monolayers and heterostructures. In order to probe the effects of strain on our samples, we choose to characterize with Raman spectroscopy a simple yet powerful way to measure lattice properties and their coupling to the electronic degrees of freedom. Strains were applied in both zigzag and armchair directions (Y and X axes in Fig. 1(e) in our experiments. Our Raman setup with 532 nm excitation wavelength is shown in Fig. 1(f) The measurements were performed while controlling for the incident light's polarization (Ei) direction (th in Fig. 1(e) For each experiment, Raman spectra were collected in both the parallel(Es Ei) and crosspolarized (Es Ei) detector geometries, shown with standard notations Z(YY)Z and Z(YX)Z respectively. In our experiments, we found no dependence of the Raman spectra on the angle of incidence relative to the crystallographic axis at zero strain. We therefore fix our incidence angle to the Y direction, and measure the unpolarized, parallel polarized and cross polarized Raman spectra at each value of strain which is applied in the X direction. We first discuss the properties of monolayer WSe2. Shown in Fig. 2(a) are a sequence of spectra taken at different values of strain in the unpolarized, parallel and cross polarization geometries. Previous Raman spectroscopy measurements performed on monolayer WSe2 have identified three vibrational modes [30 32] termed A, E and 2LA. A is an out of plane phonon mode in which the top and bottom chalcogen atoms vibrate in opposing directions; while E is in plane mode where the metal atoms vibrate out of phase with the chalcogen atoms [33] The 2LA mode results from a double resonance process involving two phonons from the LA branch. Second order processes can in general give rise to a complex lineshape in the Raman spectrum; yet, in the case of WSe2 we find that a single Lorentzian can be used to model well the 2LA mode lineshape. Although Aand E modes are nearly degenerate, they can be distinguished from each other by polarization dependency of their intensities. The out of plane, symmetric A mode disappears due to its symmetry in the cross polarization geometry, leaving behind only the E mode. Our spectra in the cross polarization geometry can thus be modeled well as the sum of two Lorentzian peaks corresponding to E and 2LA modes. Information of the E mode position can then be used to fit the spectra seen in the parallel polarization geometry in order to extract the nearlyoverlapping A mode position. Having understood the polarization dependent Raman spectra of unstrained monolayer WSe2, we apply uniaxial strains and measure the Raman response. The effects of uniaxial strain up to 1% on monolayer WSe2 has previously been experimentally investigated via unpolarized Raman [17] and absorption spectroscopy [34] Raman spectra under increasing uniaxial strain up to 3% are shown in Fig. 2(a) A close examination of spectral lineshapes in the cross polarization geometry shows that the E mode becomes broader with increasing strain. In general, we expect that the initially doubly degenerate E mode splits on the application of strain into E and E. The displacement eigenvector of the E mode is orthogonal to the direction of strain, while it is parallel for the Emode, as has previously been observed for MoS2 and graphene [3, 16, 21] While we cannot observe a complete separation of the E and E modes in our data, it is nevertheless straightforward to fit the lineshape to two Lorentzian functions and extract the splitting as a function of strain, as shown in Fig. 2(e) The splitting of the E mode under tensile strain due to the anharmonictiy of molecular potentials can be described by Gruneisen parameter g |oE' |oE' 2oE'(1 v) and the shear deformation potential b |oE' |oE' 2oE'(1 v) where oE' is the frequency of E mode, oE' and oE' are the frequency shifts of split modes per unit percent strain and v is Poisson's ratio which is 0.27 for our substrates. We obtain values of g 0.38 b 0.10 for WSe2 which are smaller than those reported for graphene [2, 3] Using t
author_names: Abdollah Motmaen Dadgar

Declan Scullion

Kyung Nam Kang

Daniel V Esposito

Eui-Hyeok Yang

Irving P Herman

Marcos A Pimenta

Elton J G Santos

Abhay N Pasupathy
title: Achieving Large, Tunable Strain in Monolayer Transition Metal Dichalcogenides
year: 2017

abstract: Strain engineering is an effective way to tune the thermal and electrical properties of novel two dimensional (2D) materials. In this work, first principles density functional theory (DFT) is used to systematically investigate the strain dependent lattice thermal conductivity and phonon properties of buckled arsenene and phosphorene, which are the 2D materials with the highest thermal conductivities among monolayers in group VA. We implemented an iterative self consistent solution to the Peierls Boltzmann transport equation (PBTE) Our results showed that the thermal conductivity in both monolayers exhibits an up and down behavior when biaxial tensile strain is applied in the range from 0% to 9% The peak values in the thermal conductivities occur at 5% of strain in arsenene and 3% in phosphorene, with the maximum conductivities of strained arsenene and phosphorene being 1.4 and 1.2 times higher than those of unstrained samples, respectively. We provide a rigorous description of the underlying phonon physics responsible for these thermal responses to strain, addressing the interplay between phonon group velocities, heat capacities, and relaxation times. The acoustic optical phonon band gaps in arsenene and phosphorene were found to reduce with strain, being the reduction more significant in phosphorene. Our results also showed that the use of the single mode relaxation time approximation (SMRTA) predict substantially lower thermal conductivities for arsenene and phosphorene than those predicted by the iterative solution of the PBTE.
author_names: Armin Taheri

Carlos da Silva

Cristina H Amon
title: Effects of biaxial tensile strain on the first principles driven thermal conductivity of buckled arsenene and phosphorene.
venue: Physical chemistry chemical physics PCCP
year: 2018

abstract: [Synthesis and Terahertz Applications of Large Area Monolayer Graphene] by Minjie Wang Monolayer graphene, successfully isolated in 2004 for the first time, is the first member of the class of materials called two dimensional (2D) materials. It consists of a 2D honeycomb lattice of sp2 bonded carbon atoms, possessing extraordinary mechanical, chemical, and physical properties. The unique band structure and gate tunability of graphene are expected to result in novel highfrequency (THz) and optical phenomena. In this thesis work, we used two different ways to grow graphene on a copper foil via chemical vapor deposition (CVD) One method synthesized continuous, large size monolayer graphene, while the other method created signalcrystal graphene with no domain boundaries. We transferred grown graphene from copper foil to SiO2/Si substrates by the wet etch method with four types of copper etchants that are commonly used by researcher: HNO3, FeCl3, (NH4)2S2O8, and a commercial copper etchant. Further tests and analysis showed that the commercial copper etchant is the best for transfer purposes from the perspective of structural integrity, amount of residues, and doping carrier concentration. We conducted strain dependent THz transmission measurements of graphene on a polyimide substrate (Kapton) using a strain controllable mechanicaloptical testing system. Experimental results showed that THz transmittance of graphene changes significantly with strain up to ~30% but no reversible change of THz transmittance was observed. On the other hand, by using a recently proposed total internal reflection (TIR) geometry, we demonstrated significant enhancement of THz wave absorption in monolayer graphene. Our scheme allowed the incident THz beam to be reflected by graphene four times at varying incidence angles, both below and above the critical angle for TIR. We observed extremely large THz absorption, especially for spolarized radiation. The experimental results are quantitatively consistent with our calculations, incorporating realistic values of carrier scattering time and Fermi energy.
author_names: Minjie Wang
title: Synthesis and Terahertz Applications of Large Area Monolayer Graphene
year: 2016

abstract: We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi LAT to cover the g ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X rays; and GASP WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the g ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self Compton (SSC) scenarios. Aims. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model to data agreement in the individual model parameters, hence providing a less biased interpretation than the "single curve SSC model adjustment" typically reported in the literature. Methods. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid scan shows that the flaring activity around May 22 cannot be modeled adequately with a one zone SSC scenario (using an electron energy distribution with two breaks) while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5 month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X rays and very high energy >100 GeV, VHE) g rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA) cannot be satisfactorily reproduced by either a one zone or a two independent zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub hour timescales (detected at VHE g rays) Results. The higher variability in the VHE emission and lack of correlation with the X ray emission indicate that, at least during the 4.5 month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE g rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE g ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid scan show that there is some degeneracy in both the one zone and the two zone SSC scenarios probed, with several combinations of model parameters yielding a similar model to data agreement, and some parameters better constrained than others. The observed g ray flaring activity, with the EVPA rotation coincident with the first g ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties.
author_names: M L Ahnen

Stefano Ansoldi

Lucio Angelo Antonelli

P Antoranz

A Babic

B Banerjee

Priyadarshini Bangale

Ulisses Barres DE Almeida

J A Barrio

J Becerra Gonz'alez

W Bednarek

Elisa Bernardini

Alessio Berti

Barbara Biasuzzi

Adrian Biland

O Blanch

S Bonnefoy

G Bonnoli

F Borracci

Thomas Bretz

Sara Buson

Alessandro Carosi

Arka Chatterjee

R Clavero

Pierre Colin

E Colombo

Jose Luis Contreras

J Cortina

Stefano Covino

Paolo Da Vela

Francesco Dazzi

Alessandro De Angelis

Barbara De Lotto

Emma de Ona Wilhelmi

Federico Di Pierro

Marlene Doert

Alberto Dom'inguez

D Dominis Prester

Daniela Dorner

Michele Doro

Sabrina Einecke

D Glawion

D Elsaesser

M Engelkemeier

Vandad Fallah Ramazani

A Fern'andez-Barral

David Carreto Fidalgo

M V Fonseca

L Font

Katharina Frantzen

Christian Fruck

D Morachis Galindo

R J Garc'ia L'opez

M Garczarczyk

D Garrido Terrats

Markus Gaug

Paola Giammaria

Nikola Godinovi'c

Adiv Gonzalez Munoz

Dariusz Gora

Daniel A Guberman

D Hadasch

A Hahn

Yoshitaka Hanabata

Masaaki Hayashida

J Herrera

Juergen Hose

D Hrupec

Gareth Hughes

W Idec

Kazuhito Kodani

Yusuke Konno

H Kubo

J Kushida

Antonio La Barbera

D Lelas

E Lindfors

S Lombardi

Francesco Longo

M A L'opez

Rub'en L'opez-Coto

P Majumdar

M Makariev

K Mallot

Galina Maneva

Marina Manganaro

Karl Mannheim

Laura Maraschi

Benito Marcote

Mose Mariotti

M C Mart'inez

D Mazin

Uta Menzel

J M Miranda

R Mirzoyan

A Moralejo

E Moretti

Daisuke Nakajima

V V Neustroev

Andrzej Niedzwiecki

M Nievas Rosillo

K Nilsson

K Nishijima

K Noda

L Nogu'es

A -K Overkemping

Simona Paiano

Joaquim Palacio

M Palatiello

D Paneque

Riccardo Paoletti

Josep Maria Paredes

Xavier Paredes-Fortuny

Giovanna Pedaletti

Michele Peresano

Luca Perri

Massimo Persic

Juri Poutanen

P G Prada Moroni

E Prandini

I Puljak

Ignasi Reichardt

Wolfgang Rhode

Marc Rib'o

J Rico

J Rodriguez Garcia

T Saito

Konstancja Satalecka

S Schroder

Cornelia Schultz

Thomas Schweizer

Steven N Shore

Aimo K Sillanpaa

J Sitarek

Iva Snidaric

D Sobczynska

A Stamerra

T Steinbring

Marcel Strzys

T Suri'c

Leo O Takalo

Fabrizio Tavecchio

P Temnikov

Tomislav Terzi'c

Diego Tescaro

Masahiro Teshima

Julia Thaele

Diego F Torres

Takeshi Toyama

Aldo Treves

G Vanzo

V Verguilov

I Vovk

John E Ward

Martin Will

M H Wu

Roberta Zanin

Anushka Udara Abeysekara

Simon Archambault

Avery Archer

W Benbow

R Bird

M Buchovecky

James Henry Buckley

Viatcheslav Bugaev

Michael P Connolly

Wei Wei Cui

Hugh Dickinson

Abraham D Falcone

Qi Feng

John Park Finley

H Fleischhack

A Flinders

Lucy Fortson

G H Gillanders

Sean Griffin

Jeff Grube

Moritz Hutten

David Hanna

Jamie Holder

Thomas Brian Humensky

Philip Kaaret

Payel Kar

Nathan C Kelley-Hoskins

M P Kertzman

D Kieda

M Krause

Frank Krennrich

M J Lang

Gernot Maier

Andrew McCann

Patrick J Moriarty

Reshmi Mukherjee

Daniel Nieto

Stephan O'Brien

R A Ong

N Otte

Nahee Park

Jeremy S Perkins

Ana Pichel

Martin Pohl

Alexis Popkow

E Pueschel

Joseph F Quinn

K Ragan

Philip T Reynolds

Gordon T Richards

E Roache

Adrian C Rovero

Cameron B Rulten

Iftach H Sadeh

M Santander

Glenn H Sembroski

K Shahinyan

Igor Telezhinsky

J V Tucci

Joshua Tyler

Scott Patrick Wakely

A Weinstein

P Wilcox

Alina Wilhelm

D A Williams

Benjamin Zitzer

Stefano Villata

C M Raiteri

Hugh D Aller

M F Aller

V M Larionov

A Arkharov

Dmitry Blinov

Natalia V Efimova

Tatiana S Grishina

Vladimir A Hagen-Thorn

Evgenia N Kopatskaya

Liudmilla V Larionova

Elena G Larionova

Daria A Morozova

Ivan S Troitsky

Rolando Ligustri

Paolo Calcidese

Andrei V Berdyugin

O M Kurtanidze

M G Nikolashvili

Givi N Kimeridze

Lorand A Sigua

S O Kurtanidze

Revaz Chigladze

W P Chen

Ekaterina Koptelova

Takanori Sakamoto

Alberto Carlo Sadun

J Ward Moody

Cameron J Pace

Richard L Pearson

Yoichi Yatsu

Y A Mori

A Carraminyana

Luis Carrasco

E De la Fuente

Jay Norris

P Smith

Ann Elizabeth Wehrle

Mark A Gurwell

Alma C Zook

Claudio Pagani

Matteo Perri

M Capalbi

Andrea Cesarini

H A Krimm

Y Y Kovalev

Yu A Kovalev

Eduardo Ros

A B Pushkarev

M L Lister

Kirill V Sokolovsky

Matthias Kadler

Glenn Piner

Anne Lahteenmaki

Merja Tornikoski

Emmanouil Angelakis

Thomas P Krichbaum

Ioannis Nestoras

Lars Fuhrmann

J Anton Zensus

Pietro Cassaro

Andrea Orlati

Giuseppe Maccaferri

P Leto

Marcello Giroletti

Joseph L Richards

W Max-Moerbeck

Applied Biosciences Eth Zurich

Universita' di Udine

Infn Trieste

Inaf - National Institute for Astrophysics

Universit'a di Siena

Infn sez di Pisa

Croatian Magic Consortium

Rudjer Boskovic Institute

University of Rijeka

University of Split

University of Zagreb

Saha Institute of Nuclear Physics

Max-Planck-Institut fur extraterrestrische Physik

Universidad Complutense

Instituto de Astrof'isica de Canarias

Universidad de la Laguna

Dpto Astrof'isica

University of L'od'z

Deutsches Elektronen-Synchrotron

Institut de F'isica d'Altes Energies

The Barcelona Institute of Science

Universitat Wurzburg

Universita di Padova

Institute for Space Sciences

Technische Universitat Dortmund

Finnish Magic Consortium

Tuorla Astronomical Observatory

University of Turku

Astronomy Division

University of Oulu

Unitat de F'isica de les Radiacions

Departament de F'isica

Universitat Aut'onoma de Barcelona

Japanese Magic Consortium

The University of Tokyo

Department of Engineering Physics

Hakubi Center

Kyoto University

Tokai University

The University of Tokushima

Inst for Nucl Research

Nucl Energy

Universita' di Pisa

Now at Centro Brasileiro de Pesquisas F'isicas

Rio de Janeiro

Nasa Goddard Space Flight Center

Humboldt University of Berlin

Institut fur theoretische Physik

Berlin Germany

also at University of Trieste

now at Ecole polytechnique f'ed'erale de Lausanne

now at Max-Planck-Institut fur Kernphysik

also at Japanese Magic Consortium

now at Finnish Centre for Astronomy with Eso

also at INAF-Trieste

Dept of Physics Astronomy

University of Bologna

also at Isdc - Science Data Center for Astrophysics

A Misaki Department of Physics

Department of Physics Astronomy

University of Maryland

College Park

University of Utah

Salt lake City

Physics Department

M L Sukhadia University

Washington State University

St Louis

Fred Lawrence Whipple Observatory

Harvard--Smithsonian Center for Astrophysics

School of Cosmic Physics

University College Dublin

University of Southern California

Los P Angeles

National University of Ireland Galway

Purdue University

West Lafayette

Center for Computational Astrophysics

Tsinghua University

Iowa State University

525 Davey Lab

Pennsylvania State University

University Park

University of Minnesota

Astronomy Department

Adler Planetarium

Astronomy Museum

the Bartol Research Institute

University of Delaware

Columbia University

New York

University of Iowa

Van Allen Hall

Iowa City

DePauw University

Barnard College

Enrico Fermi Institute

University of Chicago

Instituto de Astronomia y Fisica del Espacio

Ciudad de Buenos Aires

Institute of Metal Physics

University of Potsdam

Department of Astrophysical Sciences

Cork Institute of Technology

Georgia Institute of Technology

Santa Cruz Institute for Particle Physics

Santa Cruz

Argonne National Laboratory

University of Johannesburg

South Africa

INAF-Osservatorio Astrofisico di Torino

University of Michigan

Ann Arbor

Astronomical Institute

St Petersburg State University

St Petersburg

Pulkovo Astronomical Observatory

Institute for Particle Physics

University of Crete

Foundation for Research

Circolo Astrofili Talmassons

Osservatorio Astrofisico della Regione Autonoma Valle d'Aosta

Abastumani Astrophysical Observatory

Engelhardt Astronomical Observatory

Kazan Federal University

Guangzhou University

Graduate Institute of Astronomy

National Central University

College of Materials Science

952 Engineering

Aoyama Gakuin University

Sagamihara Kanagawa

University of Colorado Denver

Brigham Young University

Tokyo Institute of Technology

Meguro City

Instituto Nacional de Astrof'isica

'optica y Electr'onica

Instututo de Astronomia y Meteorologia

Dpto de Fisica

Universidad de Guadalajara

Steward Observatory

University of Arizona

Space Telescope Science Institute

Pomona College

University of Leicester

Asi Science Data Center

Via del Politecnico

I-00133 Roma

University of Trento

Center for Space Research

Exploration in Space Science

Universities Space Research Association

Astro Space Center of the Lebedev Physical Institute

Max--Planck--Institut fur Radioastronomie

Observatori Astronomic

Universitat Politecnica de Valencia

Departament d'Astronomia i Astrof'isica

Crimean Astrophysical Observatory

Sternberg Astronomical Institute

Mcgill University

Institute of Radio Astronomy

Space Applications

Remote Sensing

National Observatory of Athens

Whittier College

Aalto University Metsahovi Radio Observatory

Inaf Istituto di Radioastronomia

Sezione di Noto

Stazione Radioastronomica di Medicina

M Guainazzi Iasfinaf Bologna

Inaf - Osservatorio Astrofisico di Catania

Cahill Center for Astronomy

California Institute of Technology
title: Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009
year: 2016

abstract: We present recent advances in understanding of the ground and excited states of the electron phonon coupled systems obtained by novel methods of Diagrammatic Monte Carlo and Stochastic Optimization, which enable the approximation free calculation of Matsubara Green function in imaginary times and perform unbiased analytic continuation to real frequencies. We present exact numeric results on the ground state properties, Lehmann spectral function and optical conductivity of different strongly correlated systems: Frohlich polaron, Rashba Pekar exciton polaron, pseudo Jahn Teller polaron, exciton, and interacting with phonons hole in the t J model.
author_names: Andrei S Mishchenko

N Nagaosa Crest

Japan Science

Technology Agency

Russian Research CenterKurchatov Institute

The University of Tokyo
title: Spectroscopic Properties of Polarons in Strongly Correlated Systems by Exact Diagrammatic Monte Carlo Method
year: 2007

abstract: Systematic self monitoring of glycaemia represents acornerstone in intensified insulin therapy. In fact,self monitoring of blood glucose (SMBG) marksprobably the most important advance in diabetescare since the discovery of insulin. However, at leasttwo aspects make conventional SMBG difficult. Fin ger pricking to obtain the droplet of blood is regardedby many patients as even more daunting and painfulthan insulin injections [1] On the other hand, spotmeasurements of blood glucose, even if performedseveral times daily, only provide an incomplete pic ture of the blood glucose changes occurring over thewhole day. A continuous and reliable in vivo glucosemonitoring system would allow diabetic patients tocheck their metabolic control at their convenience.This would supply the diabetic patient with all infor mation required to optimise insulin therapy and,possibly, to improve metabolic control. Further more acute metabolic deteriorations, such as hypo glycaemic episodes, should easily become detectableby a continuously working glucose sensor.Several minimally invasive and non invasive ap proaches have been studied to monitor blood glucosemore or less continuously: 1) Implantable subcutane ous (s.c. glucose sensors, 2) S.c. interstitial fluidsampling by microdialysis or open tissue microperfu sion, 3) Transdermal glucose monitoring systems, 4)Optical glucose sensors. The minimally invasive ap proaches (1 and 2) are based on the analysis of inter stitial fluid. Insertion of electrodes into the s.c. tissuehas not yet resulted in a glucose sensor that could beused reliably for longer periods of time in humans[2 5] Lack of biocompatibility of the electrode sur face results in drifts of the electrode signal, associatedwith a loss of glucose sensitivity. The minimally inva sive microdialysis technique and related techniquesreduce such problems by pumping a perfusatethrough a dialysis fibre inserted in the subcutaneoustissue [6 10] Glucose diffuses from the interstitialfluid into the perfusate and is measured ex vivo. Inother approaches devices are attached to the skin tocollect glucose containing fluid transdermally [11].We will not review these minimally invasive ap proaches for glycaemic monitoring but will focus onnon invasive optical glucose sensors that avoid anumber of the problems of former approaches. Wewill discuss the problems of reliable glucose monitor ing using the spectrometric absorption technologyand present a novel approach making use of the factthat the variation of blood glucose levels changes thelight scattering properties of skin tissue.In vivo glucose monitoringby light absorption measurementSome research groups are trying to develop non inva sive glucose monitoring systems based on absorptionmeasurements [12 16] Up to now, however, nonehas been converted into a reliable glucose monitoringsystem, although a number of companies have pre sented or announced glucose monitoring devices us ing similar approaches.Spectrophotometry is an established method forthe quantification of solutes in liquids. It is based onsolute specific absorption bands in the visible (VIS),near infra red (NIR) or mid infra red (MIR) spectralrange. Quantification of the solutes is possible by de termination of light attenuation caused by absorptionat a single wavelength when taking the light pathlength (i.e. the cuvette thickness) into account. Thesolution has to be clear, as light scattering would re sult in an additional attenuation of light.
author_names: Lutz Heinemann

Gunther Schmelzeisen-Redeker

On behalf of the European Society of Paediatric Radio Force
title: Non invasive continuous glucose monitoring in Type I diabetic patients with optical glucose sensors
venue: Diabetologia
year: 1998