Departmental Papers (MSE)

Document Type

Conference Paper

Date of this Version

November 2000

Abstract

We present a new Screened Bond-Order Potential (SBOP) for molybdenum in which the environmental dependence of two-center tight-binding bond integrals has been implemented via a recently developed analytic expression. These bond integrals reproduce very well the numerical ab-intio values of screened LMTO bond integrals. In particular, they display the large discontinuity in ddpi between the first and second nearest neighbor of the bcc lattice whereas they do not show any discontinuity in ddsigma. This dependence can be traced directly to the angular character of the analytic screening function and is shown to be critical for the behavior of the second nearest neighbor force constants. The new BOP eliminates the problem of the very soft T2 phonon mode at the N point that is found in most two-center tight-binding models. Preliminary study of the core structure of 1/2<111> screw dislocations performed using SBOP indicates that the core is narrower and less asymmetric than structures found in previous studies, in agreement with recent ab-initio calculations.

Comments

Copyright Materials Research Society. Reprinted from MRS Proceedings Volume 653.
2000 Fall Meeting Symposium Z
Multiscale Modeling of Materials
Publisher URL: http://www.mrs.org/members/proceedings/fall2000/z/Z6_3.pdf

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Date Posted: 01 November 2004

This document has been peer reviewed.