scholarly journals First Principles Predictions of Intrinsic Defects in Aluminum Arsenide, AlAs

2011 ◽  
Vol 1370 ◽  
Author(s):  
Peter A. Schultz
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Density Functional ◽  
Semiconductor Device ◽  
Energy Levels ◽  
Aluminum Arsenide ◽  
Functional Theory ◽  
Eigenvalue Gap ◽  
Rigorous Treatment ◽  
Simulation Results

ABSTRACTThe structures, energies, and energy levels of a comprehensive set of simple intrinsic point defects in aluminum arsenide are predicted using density functional theory (DFT). The calculations incorporate explicit and rigorous treatment of charged supercell boundary conditions. The predicted defect energy levels, computed as total energy differences, do not suffer from the DFT band gap problem, spanning the experimental gap despite the Kohn-Sham eigenvalue gap being much smaller than experiment. Defects in AlAs exhibit a surprising complexity—with a greater range of charge states, bistabilities, and multiple negative-U systems—that would be impossible to resolve with experiment alone. The simulation results can be used to populate defect physics models in III-V semiconductor device simulations with reliable quantities in those cases where experimental data is lacking, as in AlAs.

scholarly journals The effect of vacancies and the substitution of p-block atoms on single-layer buckled germanium selenide

RSC Advances ◽  
2017 ◽  
Vol 7 (60) ◽  
pp. 37815-37822 ◽  
Author(s):  
F. Ersan ◽  
H. Arkin ◽  
E. Aktürk
Keyword(s):  
Density Functional Theory ◽  
Plane Wave ◽  
Point Defects ◽  
First Principles ◽  
Density Functional ◽  
Single Layer ◽  
Functional Theory ◽  
Germanium Selenide ◽  
Spin Polarized

This paper investigates the effect of point defects of both hole (Ge, Se) and substitution doping of p-block elements, in single-layer b-GeSe, based on first principles plane wave calculations within spin-polarized density functional theory.

scholarly journals First-Principles Calculation of Laser Crystal Multiplet Levels via Hybridized Density Functional Theory and Configuration Interaction within the OLCAO Method

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Benjamin Walker
Keyword(s):  
Density Functional Theory ◽  
Configuration Interaction ◽  
First Principles ◽  
Density Functional ◽  
Energy Levels ◽  
Computational Method ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Racah Parameters ◽  
Analytic Computation

Computation of highly-localized multiplet energy levels of transition metal dopants is essential to the design of materials such as laser host crystals. A purely first-principles density functional theory-configuration interaction (DFT-CI) hybrid computational method has been developed to accurately compute multiplet energy levels for single atoms of carbon, nitrogen, oxygen, sodium, aluminum, silicon, titanium, and chromium. The multiplet energy levels have been computed with close experimental agreement in terms of magnitude and degeneracy, and the method does not depend on empirical information (i.e. Racah parameters). The computed multiplet energy level results are distributed according to term symbols, which are then compared to experimentally-observed multiplet energy levels. The hybrid method consists of analytic computation of two-electron integrals via the DFT-based orthogonalized linear combination of atomic orbitals (OLCAO) method, which are subsequently used as input for the CI-based discrete variational multi-electron (DVME) method to obtain the multiplet energy values.Keywords: exchange-correlation; elecron repulsion integral; multiplet; DVME; OLCAO; density functional theory; configuration interaction

First principles study of point defects in SnS

2014 ◽  
Vol 16 (47) ◽  
pp. 26176-26183 ◽  
Author(s):  
Brad D. Malone ◽  
Adam Gali ◽  
Efthimios Kaxiras
Keyword(s):  
Density Functional Theory ◽  
Point Defects ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Extensive Study ◽  
Functional Theory ◽  
First Principles Study

An extensive study of defects in SnS was performed using density functional theory calculations on large supercells.

INVESTIGATION OF ELECTRON TRANSPORT OF OPEN MOLECULAR STRUCTURES BASED ON FIRST PRINCIPLES THEORY

2004 ◽  
Vol 03 (04n05) ◽  
pp. 533-540 ◽  
Author(s):  
PING BAI ◽  
SHUO-WANG YANG ◽  
ER-PING LI ◽  
PING WU
Keyword(s):  
Electron Transport ◽  
First Principles ◽  
Density Functional ◽  
Bound States ◽  
Differential Resistance ◽  
Molecular Structures ◽  
Ab Initio Method ◽  
Functional Theory ◽  
Metal Structures ◽  
Simulation Results

We study the electron transport of thiolated benzene and borazine using ab initio method Transiesta through 3D atomic metal–molecule–metal structures. The calculation is based on well-established density functional theory (DFT) and nonequilibrium Green's functions (NEGF). DFT with norm conserving nonlocal pseudopotentials is used to define the atomic core and NEGF are used to calculate the charge distribution where the contributions of scattering sates and bound states to charge density are naturally accounted. The transmission functions and I–V characteristics are presented. Simulation results show that the conductance through benzene is about four times larger than through borazine. Negative differential resistance behavior is observed with borazine while saturation feature appears with benzene.

scholarly journals Electronic Transport Properties of Doped C28 Fullerene

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Akshu Pahuja ◽  
Sunita Srivastava
Keyword(s):  
Density Functional Theory ◽  
Transport Properties ◽  
Electronic Transport ◽  
First Principles ◽  
Density Functional ◽  
Energy Levels ◽  
Gold Surfaces ◽  
Functional Theory ◽  
Self Consistent ◽  
Endohedral Doping

Endohedral doping of small fullerenes like C28 affects their electronic structure and increases their stability. The transport properties of Li@C28 sandwiched between two gold surfaces have been calculated using first-principles density functional theory and nonequilibrium Green’s function formalism. The transmission curves, IV characteristics, and molecular projected self-consistent Hamiltonian eigenstates of both pristine and doped molecule are computed. The current across the junction is found to decrease upon Li encapsulation, which can be attributed to change in alignment of molecular energy levels with bias voltage.

First-Principle Calculations of the Electronic Structure and Elastic Constants of Arsenic Doped β-SiC

2011 ◽  
Vol 704-705 ◽  
pp. 492-497
Author(s):  
Zong Guo Wang ◽  
Qun Hui ◽  
Nan Pu Cheng ◽  
Chui Lin Wang
Keyword(s):  
Electronic Structure ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Energy Levels ◽  
First Principle ◽  
Band Shift ◽  
Functional Theory ◽  
Keywords Arsenic

The electronic structure and elastic constants of arsenic doped β-SiC have been studied by first principles density functional theory (DFT) calculations. The band structure, bulk modulus, and density of states were calculated. We have demonstrated that both the top of the valence and the bottom of the conduction band shift to lower energy levels. However, arsenic doped β-SiC exhibits a non-monotonic variation of the band gap and bulk modulus with the concentration of As. Keywords: arsenic doped β-SiC, electronic structure, elastic constant, first principles

First Principles Calculations of the Formation Energy of the Neutral Vacancy in Germanium

2007 ◽  
Vol 131-133 ◽  
pp. 241-246 ◽  
Author(s):  
P. Śpiewak ◽  
Krzysztof Jan Kurzydlowski ◽  
Koji Sueoka ◽  
Igor Romandic ◽  
Jan Vanhellemont
Keyword(s):  
Experimental Data ◽  
Point Defects ◽  
First Principles ◽  
Density Functional ◽  
Formation Energy ◽  
Local Density ◽  
Density Approximation ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Germanium Single Crystal

Density functional theory (DFT) with local density approximation has been used to calculate the formation energy (EF) of the neutral vacancy in germanium single crystal. It was shown that careful checking of convergence with respect to the number of k-points is necessary when calculating the formation energy of the intrinsic point defects in Ge. The formation energy of the single neutral vacancy was estimated at 2.35 eV which is in excellent agreement with published experimental data.

Intrinsic defects in gallium sulfide monolayer: a first-principles study

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 50883-50889 ◽  
Author(s):  
Hui Chen ◽  
Yan Li ◽  
Le Huang ◽  
Jingbo Li
Keyword(s):  
Density Functional Theory ◽  
Point Defects ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Theory Method ◽  
Functional Theory ◽  
Gallium Sulfide ◽  
Native Point Defects ◽  
The Density Functional Theory

The electronic and magnetic properties of native point defects, including vacancies (VGa and VS), antisites (GaS and SGa) and interstitials (Gai and Si) in monolayer and bulk GaS, were systemically studied using the density functional theory method.

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