Determination of the high c/a ratio of hexagonal metals with a semi-empirical tight-binding method

• Published in: Computational materials science Vol. 17; no. 2-4; pp. 249 - 254
• Main Authors: Béré, A, Chen, J, Hairie, A, Nouet, G, Paumier, E
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-06-2000; Elsevier Science
• Subjects: Applied sciences; Cadmium; Condensed matter: structure, mechanical and thermal properties; Crystal binding; cohesive energy; Crystalline state (including molecular motions in solids); Density matrix; Electronic energy; Exact sciences and technology; Hexagonal metals; Metals. Metallurgy; O(N) method; Physics; Recursion method; Structure of solids and liquids; crystallography; Tight-binding; Zinc; Cadmium; Electronic energy; Density matrix; O(N) method; Recursion method; Tight-binding; Hexagonal metals; Zinc; O(N) group; Total energy; Theoretical study; Lattice parameters; Hexagonal lattices; Tight binding approximation; Transition elements; Binding energy; Phase stability; Semiempirical method
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/S0927-0256(00)00033-1

A semi-empirical tight-binding potential is developed to reproduce the high c/a ratio of zinc and cadmium. In this scheme, we show that the calculation of the electronic energy by the standard recursion method with the Harrison model for the hopping integrals and their radius dependence is not able to predict c/a values higher than the ideal one γ0=8/3=1.633. Only, the recursion method limited to first neighbours has permitted to get the right c/a ratio of zinc and cadmium. The calculated energies of different structures (2H, 4H, 6H and 3C) show that the hexagonal compact structure (2H) is always most stable.