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Title: A modified Stillinger-Weber potential for TlBr and its polymorphic extension

TlBr is promising for g- and x- radiation detection, but suffers from rapid performance degradation under the operating external electric fields. To enable molecular dynamics (MD) studies of this degradation, we have developed a Stillinger-Weber type of TlBr interatomic potential. During this process, we have also addressed two problems of wider interests. First, the conventional Stillinger-Weber potential format is only applicable for tetrahedral structures (e.g., diamond-cubic, zinc-blende, or wurtzite). Here we have modified the analytical functions of the Stillinger-Weber potential so that it can now be used for other crystal structures. Second, past modifications of interatomic potentials cannot always be applied by a broad community because any new analytical functions of the potential would require corresponding changes in the molecular dynamics codes. Here we have developed a polymorphic potential model that simultaneously incorporates Stillinger-Weber, Tersoff, embedded-atom method, and any variations (i.e., modified functions) of these potentials. As a result, we have implemented this polymorphic model in MD code LAMMPS, and demonstrated that our TlBr potential enables stable MD simulations under external electric fields.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  2. Univ. of New Mexico, Albuquerque, NM (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1237468
Report Number(s):
SAND--2015-1656J
Journal ID: ISSN 1927-0585; 579716
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Science Research
Additional Journal Information:
Journal Volume: 4; Journal Issue: 3; Journal ID: ISSN 1927-0585
Publisher:
Canadian Center of Science and Education
Research Org:
Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sandia National Laboratories, Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 36 MATERIALS SCIENCE interatomic potential; molecular dynamics; TlBr crystal; structure evolution; radiation detection semiconductor