Density-functional calculation for quasi-two-dimensional hole gases

1994 ◽  
Vol 50 (20) ◽  
pp. 15221-15238 ◽  
Author(s):  
W. O. G. Schmitt
Keyword(s):  
Density Functional ◽  
Two Dimensional ◽  
Density Functional Calculation

Two-dimensional germanane and germanane ribbons: density functional calculation of structural, electronic, optical and transport properties and the role of defects

RSC Advances ◽  
2016 ◽  
Vol 6 (34) ◽  
pp. 28298-28307 ◽  
Author(s):  
Jun Zhao ◽  
Hui Zeng
Keyword(s):  
Transport Properties ◽  
Green's Function ◽  
First Principles ◽  
Density Functional ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Density Functional Calculation ◽  
Non Equilibrium Green’S Function ◽  
Non Equilibrium

We have performed first principles calculations combined with non-equilibrium Green’s function to study the structural, electronic, optical and transport properties of two-dimensional germanane and germanane ribbons.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Design and Synthesis of Two-Dimensional Covalent Organic Frameworks with Four-Arm Cores: Prediction of Remarkable Ambipolar Charge-Transport Properties

2019 ◽  
Author(s):  
Simil Thomas ◽  
Hong Li ◽  
Raghunath R. Dasari ◽  
Austin Evans ◽  
William Dichtel ◽  
...  
Keyword(s):  
Charge Transport ◽  
Organic Semiconductors ◽  
Density Functional ◽  
Polymer Networks ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
X Ray Diffraction ◽  
Zinc Porphyrin ◽  
Design And Synthesis ◽  
Predicted Values

<p>We have considered three two-dimensional (2D) π-conjugated polymer networks (i.e., covalent organic frameworks, COFs) materials based on pyrene, porphyrin, and zinc-porphyrin cores connected <i>via</i> diacetylenic linkers. Their electronic structures, investigated at the density functional theory global-hybrid level, are indicative of valence and conduction bands that have large widths, ranging between 1 and 2 eV. Using a molecular approach to derive the electronic couplings between adjacent core units and the electron-vibration couplings, the three π-conjugated 2D COFs are predicted to have ambipolar charge-transport characteristics with electron and hole mobilities in the range of 65-95 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup>. Such predicted values rank these 2D COFs among the highest-mobility organic semiconductors. In addition, we have synthesized the zinc-porphyrin based 2D COF and carried out structural characterization via powder X-ray diffraction and surface area analysis, which demonstrates the feasability of these electroactive networks.</p>

Anisotropic gap of superconductingCaC6: A first-principles density functional calculation

2007 ◽  
Vol 75 (2) ◽  
Author(s):  
A. Sanna ◽  
G. Profeta ◽  
A. Floris ◽  
A. Marini ◽  
E. K. U. Gross ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Calculation

scholarly journals Complex magnetism of the two-dimensional antiferromagnetic Ge2F: from a Néel spin-texture to a potential antiferromagnetic skyrmion

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8654-8663
Author(s):  
Fatima Zahra Ramadan ◽  
Flaviano José dos Santos ◽  
Lalla Btissam Drissi ◽  
Samir Lounis
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Low Energy ◽  
Two Dimensional ◽  
Functional Theory ◽  
2D Material ◽  
Energy Models ◽  
Spin Texture

Based on density functional theory combined with low-energy models, we explore the magnetic properties of a hybrid atomic-thick two-dimensional (2D) material made of germanene doped with fluorine atoms in a half-fluorinated configuration (Ge2F).

scholarly journals Performance of SCAN Meta-GGA Functionals on Nonlinear Mechanics of Graphene-Like g-SiC

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 120
Author(s):  
Qing Peng
Keyword(s):  
Mechanical Properties ◽  
Density Functional ◽  
Large Strains ◽  
Two Dimensional ◽  
Nonlinear Mechanics ◽  
Generalized Gradient ◽  
Mechanics Of Materials ◽  
Nonlinear Mechanical ◽  
Direct Band ◽  
Simulations And Modeling

Although meta-generalized-gradient approximations (meta-GGAs) are believed potentially the most accurate among the efficient first-principles calculations, the performance has not been accessed on the nonlinear mechanical properties of two-dimensional nanomaterials. Graphene, like two-dimensional silicon carbide g-SiC, has a wide direct band-gap with applications in high-power electronics and solar energy. Taken g-SiC as a paradigm, we have investigated the performance of meta-GGA functionals on the nonlinear mechanical properties under large strains, both compressive and tensile, along three deformation modes using Strongly Constrained and Appropriately Normed Semilocal Density Functional (SCAN) as an example. A close comparison suggests that the nonlinear mechanics predicted from SCAN are very similar to that of Perdew-Burke-Ernzerhof (PBE) formulated functional, a standard Density Functional Theory (DFT) functional. The improvement from SCAN calculation over PBE calculation is minor, despite the considerable increase of computing demand. This study could be helpful in selection of density functionals in simulations and modeling of mechanics of materials.

scholarly journals Two-dimensional iodine-monofluoride epitaxy on WSe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yung-Chang Lin ◽  
Sungwoo Lee ◽  
Yueh-Chiang Yang ◽  
Po-Wen Chiu ◽  
Gun-Do Lee ◽  
...  
Keyword(s):  
Density Functional ◽  
Surface Passivation ◽  
Hexagonal Lattice ◽  
Chemical Vapor ◽  
Growth Promoter ◽  
Two Dimensional ◽  
Epitaxial Relationship ◽  
Chemical Vapor Deposition Growth ◽  
Scanning Transmission ◽  
Great Possibility

AbstractInterhalogen compounds (IHCs) are extremely reactive molecules used for halogenation, catalyst, selective etchant, and surface modification. Most of the IHCs are unstable at room temperature especially for the iodine-monofluoride (IF) whose structure is still unknown. Here we demonstrate an unambiguous observation of two-dimensional (2D) IF bilayer grown on the surface of WSe2 by using scanning transmission electron microscopy and electron energy loss spectroscopy. The bilayer IF shows a clear hexagonal lattice and robust epitaxial relationship with the WSe2 substrate. Despite the IF is known to sublimate at −14 °C and has never found as a solid form in the ambient condition, but surprisingly it is found stabilized on a suitable substrate and the stabilized structure is supported by a density functional theory. This 2D form of IHC is actually a byproduct during a chemical vapor deposition growth of WSe2 in the presence of alkali metal halides as a growth promoter and requires immediate surface passivation to sustain. This work points out a great possibility to produce 2D structures that are unexpected to be crystallized or cannot be obtained by a simple exfoliation but can be grown only on a certain substrate.

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