Structural, elastic, vibrational and electronic properties of amorphous Al 2O 3 from ab initio calculations

Davis, S; Gutierrez G.

Keywords: dynamics, chemistry, electron, state, density, localization, cell, structure, bands, range, states, aluminum, quantum, frequency, elastic, oxides, ab, molecular, moduli, correlations, function, properties, electronic, amorphous, orders, calculation, Calculations, of, Short, Vibrational, initio, Interatomic, super, First-principles, Bond-stretching, Ionicities

Abstract

First-principles molecular dynamics calculations of the structural, elastic, vibrational and electronic properties of amorphous Al 2O 3, in a system consisting of a supercell of 80 atoms, are reported. A detailed analysis of the interatomic correlations allows us to conclude that the short-range order is mainly composed of AlO 4 tetrahedra, but, in contrast with previous results, also an important number of AlO 6 octahedra and AlO 5 units are present. The vibrational density of states presents two frequency bands, related to bond-bending and bond-stretching modes. It also shows other recognizable features present in similar amorphous oxides. We also present the calculation of elastic properties (bulk modulus and shear modulus). The calculated electronic structure of the material, including total and partial electronic density of states, charge distribution, electron localization function and the ionicity for each species, gives evidence of correlation between the ionicity and the coordination for each Al atom. © 2011 IOP Publishing Ltd.

Más información

Título de la Revista: Journal of Physics: Condensed Matter
Volumen: 23
Número: 49
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2011
URL: http://www.scopus.com/inward/record.url?eid=2-s2.0-82455220814&partnerID=q2rCbXpz