Modeling of copper-carbon solid solutions
D.E. Ellis , K.C. Mundim, D. Fuks, S. Dorfman, A. Berner
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
3: (1-2) 123-127 MAR 2000

Abstract:
                The atomistic simulations in the framework of the Generalized Simulated Annealing approach (GSA) and classical force fields lead to very reasonable relaxed geometries around the carbon interstitial in O-, T-, and TS-sites. We have thus shown that a highly efficient energy-sampling and relaxation scheme, implemented with tight constraints on a limited volume, provides a powerful steering mechanism for selection of geometries suitable for detailed investigation by first-principles methods. The results, based upon harmonic interactions between Cu atoms and a van der Waals interaction between Cu and C, predict the relaxed O-site to be more stable than the T-site by similar to 1.2 eV, in accordance with general expectations.
                The TS barrier to O-O diffusion is found to be similar to 0.8 eV, at a temperature of 0 K; the TS exhibits a strong local axial distortion of the pseudo-octahedral environment. The Density Functional results indicate a charge transfer of similar to 1 e to carbon, mostly from the first neighbor shell, in all relaxed environments studied. Bond-order data show the Cu-C interaction to be bonding in nature, despite the net 'repulsive interaction' leading to a surface state of lower net energy.

KeyWords Plus:   EMBEDDED-CLUSTER MODEL, ALLOYS

Addresses:
Ellis DE, Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA.
Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA.
Univ Bahja, Inst Phys, Salvador, BA, Brazil.
Technion Israel Inst Technol, Dept Phys, IL-32000 Haifa, Israel.
Technion Israel Inst Technol, Dept Mat Engn, IL-32000 Haifa, Israel.

Publisher      :  ELSEVIER SCI LTD, OXFORD
IDS Number :  358EX
ISSN             :  1369-8001