A simple transferable interatomic potential model for binary oxides applied to bulk α-Al2O3 and the (0001) α-Al2O3 surface

• Published in: Journal of crystal growth 2006-04, Vol.290 (1), p.235-240
• Main Authors: JIZHONG SUN, STIRNER, T, HAGSTON, W. E, LEYLAND, A, MATTHEWS, A
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Crystalline state (including molecular motions in solids); Exact sciences and technology; Physics; Structure of solids and liquids; crystallography; Theory of crystal structure, crystal symmetry; calculations and modeling
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2005.12.076

A simple transferable potential for binary, highly ionic oxides is derived from a previous work. In this new potential the van der Waals terms involving cations and the cation-cation short-range repulsive interactions do not appear explicitly. The potential parameters of this new model are optimised for alpha-Al2O3, MgO and CaO. Good agreement between theory and experiment is obtained for the structural parameters and lattice energies. The potential is then employed to study the relaxation of the Al-terminated (000 1) alpha-Al2-O3 surface as well as the dynamics of this surface at non-zero temperatures using the molecular dynamics method. Here it is shown that the new potential predicts a relaxation of the (000 1) alpha-Al2O3 surface which is consistent with experiment and shell model calculations. Finally, the calculated dynamical features of the (0001) alpha-Al2O3 surface are explained in terms of a combination of the loss of translational symmetry and the resulting relaxation of the surface atoms.