First-principles total-energy calculations of atomic and electronic structure in relaxedSi1−x−yGexCy

1999 ◽  
Vol 60 (19) ◽  
pp. 13547-13554 ◽  
Author(s):  
M. Ohfuti ◽  
M. Ikeda ◽  
Y. Awano ◽  
N. Yokoyama
Keyword(s):  
Electronic Structure ◽  
Total Energy ◽  
First Principles ◽  
Energy Calculations ◽  
Atomic And Electronic Structure

First-Principles Investigations of the Atomic and Electronic Structure of Pb, Sn and Ge Adsorbed on the ${\rm Ge}(111)\mbox{-}(\sqrt{3}\times\sqrt{3})$ Surface

1998 ◽  
Vol 05 (01) ◽  
pp. 105-110 ◽  
Author(s):  
K. Würde ◽  
P. Krüger ◽  
A. Mazur ◽  
J. Pollmann
Keyword(s):  
Electronic Structure ◽  
Total Energy ◽  
First Principles ◽  
Group Iv ◽  
Striking Result ◽  
Group Iv Elements ◽  
Atomic And Electronic Structure

Submonolayer adsorption of group-IV elements (Ge, Sn, Pb) on the Ge(111) surface has been investigated using first-principles pseudopotential total-energy and force calculations. The most prominent adsorption geometries, namely T4 and H3, are compared with respect to their atomic and electronic structure. As the most striking result, our calculations favor adsorption of adatoms in thresfold-symmetric T4 sites for all three different adatom species in agreement with earlier predictions and experiment.

Atomic Hydrogen in GaN

1995 ◽  
Vol 378 ◽  
Author(s):  
Jürg Neugebauer ◽  
Chris G. Van de Walle
Keyword(s):  
Electronic Structure ◽  
Nitrogen Atom ◽  
Total Energy ◽  
Diffusion Barrier ◽  
First Principles ◽  
Atomic Hydrogen ◽  
Interstitial Site ◽  
Energy Calculations ◽  
Tetrahedral Interstitial Site ◽  
Cubic Gan

ABSTRACTBased on extensive first-principles total-energy calculations we study the electronic structure, atomic geometry and energetics of atomic hydrogen in cubic GaN. All charge states of hydrogen (H+, H0, H-) are examined. For H- the gallium tetrahedral interstitial site is energetically most stable. All other sites are much higher in energy, indicating a high diffusion barrier for H- in GaN. H+ favors positions on a sphere with a radius of ≈ 1 Å and a nitrogen atom in the center. Among these positions the nitrogen antibonding site is energetically most stable. An unexpectedly large negative-U effect (U = —2.5eV) indicates that H0 is unstable.

Phase Stability of the Sigma Phase in Fe-Cr Based Alloys

1995 ◽  
Vol 408 ◽  
Author(s):  
Marcel Il. F ◽  
Sluiter. Koivan Esfurjani ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Total Energy ◽  
Phase Stability ◽  
First Principles ◽  
Finite Temperature ◽  
Sigma Phase ◽  
Complex Structure ◽  
Unit Cell ◽  
Energy Calculations ◽  
Cluster Variation ◽  
The Stability

AbstractThe FeCr sigma phase is a good example of a complex structure: it. has 30 atoms in the unit cell and 5 inequivalent lattice sites, and it belongs to the class of tetrahedrally close packed structures, also known as Frank-Kaspar structures. So far. such structures have riot been treated within a first-principles statistical thermodynamics framework. It will be shown that dtlme to advances in algorithms and hardware important features of the phase stability of complex phases can be computed. The factors which affect the stability of the sigma phase have been studied using carefully selected supercells for electronic total energy calculations. cluster variation calc:ulations in the tet.rahedron approximation were performed to evaluate the effect of partial disorder and of finite temperature. The preferred occupancy of the 5 lattice sites has been investigated and is compared with experimental determinations.

Real-space implementation of nonlocal pseudopotentials for first-principles total-energy calculations

1991 ◽  
Vol 44 (23) ◽  
pp. 13063-13066 ◽  
Author(s):  
R. D. King-Smith ◽  
M. C. Payne ◽  
J. S. Lin
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Real Space ◽  
Energy Calculations

A Theoretical Study of p-Type Doping of ZnO: Problems and Solutions

2001 ◽  
Vol 666 ◽  
Author(s):  
Yanfa Yan ◽  
S.B. Zhang ◽  
S.J. Pennycook ◽  
S.T. Pantelides
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Theoretical Study ◽  
Energy Calculations ◽  
Defect Complexes ◽  
New Approaches ◽  
Impurity Defect ◽  
Problems And Solutions ◽  
P Type ◽  
Made In

ABSTRACTWe present results of a comprehensive set of first-principles total-energy calculations of native and impurity-defect complexes in ZnO and use these results to elucidate the problems that occur in efforts to achieve p-type doping. The analysis naturally leads to new approaches that are likely to overcome the difficulties. The results provide detailed explanations of recent puzzling observations made in attempts to produce p-type ZnO.

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