Search query: Single and bilayer bismuthene structure

Related papers:

abstract: Based on first principles density functional theory calculations, we systemically study the properties of two dimensional buckled single layer bismuth (b bismuthene) The structure, stability, and electronic properties are mainly discussed by PBE SOC method and the hybrid functional HSE06 method is used to further revise the band gap. The optimized b bismuthene is determined to be dynamically and thermally stable with an indirect band gap. In particular, there is a peculiar Rashba spin splitting emerging in the valence band maximum (VBM) states. Interestingly, the Rashba energy could be effectively modulated by in layer biaxial strain. By applying in layer biaxial strain, one can find that b bismuthene has indirect direct band gap and semiconductor semimetal transitions. Moreover, we also study the electronic structure of bilayer b bismuthene that is sensitively dependent on the interlayer distance. We demonstrate that the electric field (E field) leads to a breaking of the Rashba type splitting near the VBM of single b bismuthene. More importantly, there is a synergistic effect when both strain and electric field are applied at the same time. The E field induced band splitting character could be modified by the strain strength. Thus, this study indicates that b bismuthene may be a potential material in both electronic and spintronic devices.
author_names: Ming-yang Liu

Yang Huang

Qingyuan Chen

Ze-yu Li

Chao Cao

Yao He
title: Strain and electric field tunable electronic structure of buckled bismuthene
year: 2017

abstract: Soon after the synthesis of two dimensional (2D) ultrathin black phosphorus and fabrication of field effect transistors thereof, theoretical studies have predicted that other group VA elements (or pnictogens) N, As, Sb, and Bi can also form stable, single layer (SL) structures. These were nitrogene in a buckled honeycomb structure, arsenene, antimonene, and bismuthene in a buckled honeycomb, as well as washboard and square octagon structures with unusual mechanical, electronic, and optical properties. Subsequently, theoretical studies are followed by experimental efforts that aim at synthesizing these novel 2D materials. Currently, research on 2D pnictogens has been a rapidly growing field revealing exciting properties, which offers diverse applications in flexible electronics, spintronics, thermoelectrics, and sensors. This review presents an evaluation of the previous experimental and theoretical studies until 2019, in order to provide input for further research attempts in this field. To this end, we first reviewed 2D, SL structures of group VA elements predicted by theoretical studies with an emphasis placed on their dynamical and thermal stabilities, which are crucial for their use in a device. The mechanical, electronic, magnetic, and optical properties of the stable structures and their nanoribbons are analyzed by examining the effect of external factors, such as strain, electric field, and substrates. The effect of vacancy defects and functionalization by chemical doping through adatom adsorption on the fundamental properties of pnictogens has been a critical subject. Interlayer interactions in bilayer and multilayer structures, their stability, and tuning their physical properties by vertical stacking geometries are also discussed. Finally, our review is concluded by highlighting new research directions and future perspectives on the challenges in this emerging field.
author_names: Fatih Ersan

D Kecik

V Ongun Ozcelik

Yelda Kadioglu

Olcay Uzengi Akturk

Engin Durgun

Ethem Akturk

Salim Ciraci
title: Two dimensional pnictogens: A review of recent progresses and future research directions
venue: Applied Physics Reviews
year: 2019

abstract: The perfect switching between crystal phases with different electronic structure in III V nanowires allows for the design of superstructures with quantum wells only a single atomic layer wide. However, it has only been indirectly inferred how the electronic structure will vary down to the smallest possible crystal segments. We use low temperature scanning tunneling microscopy and spectroscopy to directly probe the electronic structure of Zinc blende (Zb) segments in Wurtzite (Wz) InAs nanowires with atomic scale precision. We find that the major features in the band structure change abruptly down to a single atomic layer level. Distinct Zb electronic structure signatures are observed on both the conduction and valence band sides for the smallest possible Zb segment: a single InAs bilayer. We find evidence of confined states in the region of both single and double bilayer Zb segments indicative of the formation of crystal segment quantum wells due to the smaller band gap of Zb as compared to Wz. In contrast to the internal electronic structure of the nanowire, surface states located in the band gap were found to be only weakly influenced by the presence of the smallest Zb segments. Our findings directly demonstrate the feasibility of crystal phase switching for the ultimate limit of atomistic band structure engineering of quantum confined structures. Further, it indicates that band gap values obtained for the bulk are reasonable to use even for the smallest crystal segments. However, we also find that the suppression of surface and interface states could be necessary in the use of this effect for engineering of future electronic devices.
author_names: Johan V Knutsson

Sebastian Lehmann

Martin Hjort

Edvin Lundgren

Kimberly A Dick

Rainer Timm

Anders Mikkelsen
title: Electronic Structure Changes Due to Crystal Phase Switching at the Atomic Scale Limit.
venue: ACS nano
year: 2017

abstract: The bilayer formation properties of single component acyl chains of varying length and extent of unsaturation are compared using Langmuir monolayer flow. Four series of structural motifs in the flowing film were considered: linked oleyl chains; chains with a single cis double bond over a range of total chain lengths; chains of the same length with 1 5 cis double bonds; molecules which flow that do not have the standard cis double bond in the chain. Slower flow rates were observed for Langmuir films with increased numbers of linked oleyl chains due to the enhanced interlayer coupling between the flowing and stationary films. Slower flow rates were also observed with increased acyl chain length due to the increased intralayer coupling between the flowing molecules. More rapid flow rates were observed as the number of double bonds within the film forming material was increased, due to both the decreased inter and intralayer coupling. While no single structural feature is common to molecules that undergo mo.
author_names: Adam B Steel

++ and Brady J Cheek

Cary James Miller
title: Langmuir Monolayer Flow across Hydrophobic Surfaces. 3. Influence of Acyl Chain Structure on Supported Bilayer Formation Rates
year: 2001

abstract: Neutron reflectivity has been used to study the structure of deposited phospholipid bilayers in the gel phase and the modifications induced by the presence of a 16 amino acid peptide, the third helix of the Antennapedia homeodomain, p Antp43 58. The phospholipids were dipalmitoyl phosphatidylcholine (DPPC) and mixtures of DPPC with 10% mol/mol of the negatively charged dipalmitoyl phosphatidylserine (DPPS) They were deposited on silicon single crystals by using the Langmuir Schaeffer technique. By pushing the resolution of neutron reflectivity measurements, the bilayer structure was determined at 1 A precision. The thickness of the thin water layer between the substrate and the phospholipids was found to be 5 1 A, that of the headgroups 9 1 A and that of the chains 36 1 A. The deposited bilayer had the same roughness, 5 1 A, as the substrate itself. After peptide insertion, the thickness and roughness of DPPC bilayers did not change while the peptide appeared uniformly distributed in the interfac.
author_names: Giovanna Fragneto

Francois Graner

Thierry Charitat

++ and P Dubos

E Bellet-Amalric
title: Interaction of the Third Helix of Antennapedia Homeodomain with a Deposited Phospholipid Bilayer: A Neutron Reflectivity Structural Study
year: 2000

abstract: Virtually all structures in living cells are defined by lipid bilayers. Many molecular components can diffuse along these 2 dimensional structures, sampling all or part of the membrane, and this diffusion is central to their function. Supported lipid bilayers capture this membrane fluidity and have been used to study a wide range of membrane associated biomolecules.1 4 Recently, several techniques have been developed to microfabricate barriers on glass substrates to direct lipid bilayer selfassembly, facilitating the patterning of multiple, isolated membrane regions, or corrals, on a single substrate.5 12 The resultant corrals are typically of identical composition; however, a handful of strategies, including spatially directed photochemical transformations11 and membrane stamping,8,13 can be used to produce bilayer arrays with specific composition variations in different corrals. These composition arrays are desirable for investigating numerous biological systems, including how lipid and/or protein composition affects binding of membrane associated receptors with their ligands or each other, cellular processes such as intracellular protein modification and trafficking, and cell activation. In this communication, we introduce a robust approach that, for a wide variety of situations, greatly simplifies the production of large scale parallel bilayer arrays with defined variations in composition. The method, outlined in Figure 1, is based on exposing a prepatterned surface to a gradient of vesicles of various compositions created by flow and taking advantage of irreversible binding of vesicles to a substrate, subsequent fusion into a bilayer, and lipid mixing within each corralled region. For demonstration purposes, we fabricated a simple, millimeter scale, converging channel out of poly(dimethylsiloxane) (PDMS, Sylgard 184; Dow Corning) elastomer (Figure 1A) One wall of the channel consisted of a glass coverslip containing microcontact printed9,10,14 16 grid lines of fibronectin;17 however, any of a variety of materials can be used to create these barriers.5,8,10,12 The elastomer channel was filled with water, and then two solutions of vesicles were manually pumped through the channel as illustrated in Figure 1B. For visualization purposes, each solution contained vesicles supplemented with a small amount of a different fluorescently labeled lipid;18 conceptually, this technique is compatible with any biomolecule that can be incorporated into lipid bilayers by vesicle fusion. Downstream of the convergence, the two solutions partially mix by diffusion,19 exposing the micropatterned array to a controllable, spatially defined gradient of the two types of vesicles. The vesicles are irreversibly captured on the micropatterned coverslip, subsequently rupturing and fusing into a continuous supported lipid bilayer.3,4,21 The local composition of the bilayer reflects the distribution of vesicles exposed to the surface. Because the bilayer is a 2 dimensional fluid, any nonuniformity in membrane composition will be erased by lateral diffusion.10,11 The presence of barriers, however, limits this mixing to defined Address correspondence to this author. Phone: (650) 723 4482. Fax: (650) 723 4817. E mail: Sboxer@Stanford.edu. (1) Dori, Y. Bianco Peled, H. Satija, S. K. Fields, G. B. McCarthy, J. B. Tirrell, M. J. Biomed. Mater. Res. 2000, 50, 75 81. (2) Grakoui, A. Bromley, S. K. Sumen, C. Davis, M. M. Shaw, A. S. Allen, P. M. Dustin, M. L. Science 1999, 285, 221 7. (3) McConnell, H. M. Watts, T. H. Weis, R. M. Brian, A. A. Biochim. Biophys. Acta 1986, 864, 95 106. (4) Sackmann, E. Science 1996, 271, 43 8. (5) Cremer, P. S. Yang, T. L. J. Am. Chem. Soc. 1999, 121, 8130 1. (6) Groves, J. T. Ulman, N. Boxer, S. G. Science 1997, 275, 651 3. (7) Cremer, P. S. Groves, J. T. Kung, L. A. Boxer, S. G. Langmuir 1999, 15, 3893 6. (8) Hovis, J. S. Boxer, S. G. Langmuir 2000, 16, 894 7. (9) Kam, L. Boxer, S. G. J. Biomed. Mater. Res. Accepted for publication. (10) Kung, L. A. Kam, L. Hovis, J. S. Boxer, S. G. Langmuir 2000, 16, 6773 6. (11) Kung, L. A. Groves, J. T. Ulman, N. Boxer, S. G. AdV. Mater. 2000, 12, 731 4. (12) van Oudenaarden, A. Boxer, S. G. Science 1999, 285, 1046 8. (13) Hovis, J. S. Boxer, S. G. In preparation. (14) Kumar, A. Whitesides, G. M. Appl. Phys. Lett. 1993, 63, 4. (15) Bernard, A. Delamarche, E. Schmid, H. Michel, B. Bosshard, H. R. Biebuyck, H. Langmuir 1998, 14, 2225 9. (16) James, C. D. Davis, R. Meyer, M. Turner, A. Turner, S. Withers, G. Kam, L. Banker, G. Craighead, H. Isaacson, M. Turner, J. Shain, W. IEEE Trans. Biomed. Eng. 2000, 47, 17 21. (17) The use of proteins as barrier materials can confer additional biological activity to patterned lipid bilayer surfaces; we have used fibronectin barriers to promote adhesion of anchorage dependent cells onto lipid bilayer substrates, directing the interaction of these cells with the membrane patches.9 Here, fibronectin was labeled with Cascade Blue (Molecular Probes) to facilitate visualization of the micropatterned barriers. (18) Small unilamellar vesicles (SUVs) were prepared from dilauroylphosphatidylcholine (DLPC. Avanti) supplemented with either 1 mol of TexasRed DHPE (TR DHPE. Molecular Probes) 2 mol of NBD DHPE (Avanti) or 0.5 mol of DiD (Molecular Probes) Lipids were reconstituted in water (5 mg lipids/mL) then extruded10 through 50 nm pore membranes (Avanti) These stock solutions were diluted 1:3 (v/v) in aqueous buffer (pH 7.0) prior to use. Images of fluorescently labeled lipids and proteins were collected using appropriate filter sets, and are presented in false color as indicated in the figure legends. Figure 1. (A) Schematic illustration of the converging flow configuration used to produce limited mixing of two types of vesicles in solution. Two layers of poly(dimethylsiloxane) elastomer were cut using a template, oxidized in an air plasma, and layered to produce three walls of the converging channel (the channel downstream of the convergence measured 1 x 5 x 10 mm3) A glass coverslip patterned with an array of corrals17 comprised the fourth wall of the channel. (B) Schematic diagram illustrating controlled mixing and surface capture onto a substrate subjected to the flow shown in panel A. The local composition of a supported lipid bilayer formed by vesicle fusion reflects the makeup and spatial distribution of vesicles (denoted here as red and green dots) that are flowed past a pre patterned surface. This compositional profile is spatially averaged as the components within each corral diffuse and mix. 12901 J. Am. Chem. Soc. 2000, 122, 12901 12902
author_names: Lance Kam and

Steven G Boxer
title: Formation of Supported Lipid Bilayer Composition Arrays by Controlled Mixing and Surface Capture
year: 2000

abstract: In this paper, we focus on the synthesis and structure of the new bis(1,3,4 oxadiazole) system 2,5 bis[2 (4 tert butylphenyl) 1,3,4 oxadiazol 5 yl]pyridine (PDPyDP) We have fabricated light emitting diodes (LEDs) using poly[2 methoxy 5 (2 ethylhexoxy) 1,4 phenylene vinylene] (MEH PPV) as the emissive material, with and without a thermally evaporated electron injection/hole blocking layer of either PDPyDP or its vinylene analogue (E) 1,2 bis[2 (4 tert butylphenyl) 1,3,4 oxadiazol 5 yl]ethene (PDVDP) or its phenylene analogue 1,4 bis[2 (4 tert butylphenyl) 1,3,4 oxadiazol 5 yl]benzene (PDPDP) PDPDP is the para isomer of OXD 7, which is a widely used molecular electron transporting material. Electroluminescence spectra indicate that light is emitted only from the MEH PPV layer. Using aluminum as the cathode, the bilayer LED with PDPyDP is considerably more efficient than the corresponding single layer device or devices with PDVDP or PDPDP as the electron injection layer.
author_names: Changsheng Wang

Gun Young Jung

Yulin Hua

Christopher Pearson

Martin R Bryce

Michael C Petty

Andrei S Batsanov

Andres E Goeta

Judith A K Howard
title: An Efficient Pyridine and Oxadiazole Containing Hole Blocking Material for Organic Light Emitting Diodes: Synthesis, Crystal Structure, and Device Performance
year: 2001

abstract: Combining infrared reflection adsorption spectroscopy and ab initio quantum chemical methods we study adsorption of water on the "bilayer terminated" surface of ice film grown on a Ru(001) substrate. The adsorption was performed at 38 K with gradual increase of the coverage from 0.14 to 0.42 ML. Only three observed infrared bands, which are associated with the free OH groups, could be used for analysis of the structure: the OH stretching bands at 3720, 3695, and 3665 cm 1. The calculated frequencies permit the assignment of these bands to the OH stretching vibrations of the single water molecules stabilized at the terminal OH groups (3720 cm 1) the terminal OH groups of the bilayer surface (3695 cm 1) and the terminal OH groups acting as a proton acceptor toward adsorbed water species (3665 cm 1) Our calculations show that at the submonolayer coverage of water the lateral H bonding interaction between the adsorbed molecules should lead to the aggregation of these molecules into small clusters. The str.
author_names: and Alexander Pelmenschikov

Hirohito Ogasawara
title: Small Clusters of Water Adsorbed on the Bilayer Terminated Ice Surface: Infrared Reflection Adsorption Spectra and Quantum Chemical Calculations
year: 2002

abstract: Near field scanning optical microscopy (NSOM) and scanning force microscopy have been employed to spatially resolve the complex morphologies, spectroscopy, and charge transfer induced fluorescence quenching efficiencies of a (perylene phenethylimide)(titanyl phthalocyanine) bilayer (PPEI/TiOPc) The PPEI/TiOPc bilayer is a typical example of a n like/p like molecular semiconductor heterojunction, which is a common component in photocells, LEDs, and other devices. NSOM polarized fluorescence and transmission dataand separate bulk X ray diffraction and spectroscopic measurementson PPEI/TiOPc bilayers and PPEI and TiOPc single layers has lead to a nanoscopic and mesoscopic picture of how vacuum deposition and subsequent solvent vapor annealing controls the local structure of these films. The layers and bilayers are highly organized, containing localized crystalline regions which are preferentially oriented relative to the substrate and PPEI/TiOPc interface. In highly annealed bilayers, only a small fraction.
author_names: David Michael Adams

Josef Kerimo

Eric J Olson

Arie Zaban

and Brian A Gregg

Paul F Barbara
title: Spatially Resolving Nanoscopic Structure and Excitonic Charge Transfer Quenching in Molecular Semiconductor Heterojunctions
year: 1997

abstract: Single crystals of NaHP2 (sodium hydrogen dipalmitate) have been prepared from mixtures of NaP (sodium palmitate) and HP (palmitic acid) in ethanol. The phase compound crystallizes in the P21/a space group, with a 9.906 A, b 7.163 A, c 45.580 A, b 92.78deg, and 4 molecules per unit cell. The arrangement of the headgroups is unique among known soap and fatty acid structures by accommodating both hydrogen bonding and electrostatic interactions. Carboxylate and acid like pairs couple perpendicular to the bilayer to accommodate a "short" hydrogen bond, and the sodium is shared among laterally adjacent carboxylate anions to create a pseudo six member ring, which adds to the crystal stability. Molecular dynamic (MD) simulations establish a set of interaction parameters to describe the structure and energetics of acid carboxylate bonds, which accounts for the solid state miscibility of HP and NaP. Infrared data, collected by ATR FTIR on very pure, powdered NaH2P3, Na2H3P5, and NaHP2 acid soap standards rev.
author_names: Matthew Lawrence Lynch

Fred C Wireko

++SS and Mounir Tarek

Michael L Klein
title: Intermolecular Interactions and the Structure of Fatty Acid Soap Crystals
year: 2001