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Title: Threshold displacement energy in GaN; Ab initio molecular dynamics study

Abstract

Large-scale ab initio molecular dynamics method has been used to determine the threshold displacement energies, Ed, along five specific directions and to determine the defect configurations created during low energy events. The Ed shows a significant dependence on direction. The minimum Ed is determined to be 39 eV along the <-1010> direction for a gallium atom and 17.0 eV along the <-1010> direction for a nitrogen atom, which are in reasonable agreement with the experimental measurements. The average Ed values determined are 73.2 and 32.4 eV for gallium and nitrogen atoms, respectively. The N defects created at low energy events along different crystallographic directions have a similar configuration (a N-N dumbbell configuration), but various configurations for Ga defects are formed in GaN.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
958483
Report Number(s):
PNNL-SA-66935
Journal ID: ISSN 0021-8979; JAPIAU; 8208; KC0201020; TRN: US1000352
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics, 105(12):123527, 1-5; Journal Volume: 105; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GALLIUM NITRIDES; MOLECULAR DYNAMICS METHOD; ATOMIC DISPLACEMENTS; DEFECTS; ab initio molecular dynamics; defect configurations; threshold displacement energies; GaN; Environmental Molecular Sciences Laboratory

Citation Formats

Xiao, H. Y., Gao, Fei, Zu, Xiaotao T., and Weber, William J.. Threshold displacement energy in GaN; Ab initio molecular dynamics study. United States: N. p., 2009. Web. doi:10.1063/1.3153277.
Xiao, H. Y., Gao, Fei, Zu, Xiaotao T., & Weber, William J.. Threshold displacement energy in GaN; Ab initio molecular dynamics study. United States. doi:10.1063/1.3153277.
Xiao, H. Y., Gao, Fei, Zu, Xiaotao T., and Weber, William J.. Thu . "Threshold displacement energy in GaN; Ab initio molecular dynamics study". United States. doi:10.1063/1.3153277.
@article{osti_958483,
title = {Threshold displacement energy in GaN; Ab initio molecular dynamics study},
author = {Xiao, H. Y. and Gao, Fei and Zu, Xiaotao T. and Weber, William J.},
abstractNote = {Large-scale ab initio molecular dynamics method has been used to determine the threshold displacement energies, Ed, along five specific directions and to determine the defect configurations created during low energy events. The Ed shows a significant dependence on direction. The minimum Ed is determined to be 39 eV along the <-1010> direction for a gallium atom and 17.0 eV along the <-1010> direction for a nitrogen atom, which are in reasonable agreement with the experimental measurements. The average Ed values determined are 73.2 and 32.4 eV for gallium and nitrogen atoms, respectively. The N defects created at low energy events along different crystallographic directions have a similar configuration (a N-N dumbbell configuration), but various configurations for Ga defects are formed in GaN.},
doi = {10.1063/1.3153277},
journal = {Journal of Applied Physics, 105(12):123527, 1-5},
number = 12,
volume = 105,
place = {United States},
year = {Thu Jun 25 00:00:00 EDT 2009},
month = {Thu Jun 25 00:00:00 EDT 2009}
}
  • Ab initio molecular dynamics simulations have been carried out to study low-energy recoil events in SrTiO3. The threshold displacement energies are shown to be strongly dependent on both the orientation and the corresponding atomic arrangement. The minimum threshold displacement energies are 13 eV for an O recoil along the <100> O-O chain, 25 eV for a Sr recoil along the <100> Sr-Sr chain and 38 eV for a Ti recoil along the <110> Ti-Ti chain. The weighted average threshold displacement energies along the primary crystallographic directions are 35.7, 53.5 and > 64.9 eV for O, Sr and Ti, respectively. Themore » interstitial configurations produced by the recoil events are <100> and <111> split-interstitials for O and Sr, respectively, together with a Ti interstitial occupying a distorted bridge position between two Sr sites. It is found that the recoil events in SrTiO3 are partial- charge transfer assisted processes, and the partial- charge transfer plays an important role in these recoil events.« less
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  • No abstract prepared.
  • Molecular dynamics (MD) simulations were used to obtain threshold displacement energies (Ed) of atoms along specific directions in MgO. In the simulation, an atom in the center of the cell was given kinetic energy along a specific crystallographic direction. The positions and site potential energies of the primary knock-on atom (pka) and all neighboring atoms were monitored as a function of time.
  • No abstract prepared.