Directional versus central-force bonding in studies of the structure and glide of 1/2 111 screw dislocations in bcc transition metals

0332923 - ÚFM 2010 RIV GB eng J - Journal Article
Gröger, Roman - Vítek, V.
Directional versus central-force bonding in studies of the structure and glide of 1/2 111 screw dislocations in bcc transition metals.
Philosophical Magazine. Roč. 89, č. 34 (2009), s. 3163-3178. ISSN 1478-6435. E-ISSN 1478-6443
R&D Projects: GA AV ČR IAA100100920
Institutional research plan: CEZ:AV0Z20410507
Keywords : transition metals * dislocation core * directional bonding
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 1.273, year: 2009

We address the differences between Finnis-Sinclair potentials and bond-order potentials (BOPs) when studying 1/2 111 screw dislocations in bcc transition metals, specifically Mo and W. These potentials differ in that the former is central-force, whereas the latter include angular bonding. The cores of 1/2 111 screw dislocations have two variants, one invariant with respect to the [-101] diad and the other not. It is the description of interatomic forces that governs both the core structure and the glide behaviour of dislocations. Whereas the results obtained with BOPs are similar for the two materials studied, Finnis-Sinclair potentials lead to a broader variety. Hence, in bcc transition metals the BOPs are a more reliable description of atomic interactions than Finnis-Sinclair potentials, but when the d band does not play any important role, the Finnis-Sinclair potentials are fully applicable.
Permanent Link: http://hdl.handle.net/11104/0178037