title: Band structure and optical properties of hexagonal In-rich In(x)Al(1-x)N alloys.
abstract: Full potential linear augmented plane wave calculations have been performed to study the electronic and optical properties of In-rich In(x)Al(1-x)N alloys in the hexagonal wurtzite structure. Compositions of x = 0.9375, 0.8125 and 0.6875 are considered which follow from replacing one, three and five In atoms by Al in the 32-atom supercell. The new form of exchange correlation, i.e. Engel-Vosko's generalized gradient approximation within density functional theory, is employed. The calculations yield the band structure and total density of states as well as the imaginary part ε(2)(ω) of the ordinary and extraordinary dielectric function. The calculated dependence of the bandgap on the composition is in good agreement with recent experimental studies. A reversal of the valence band ordering is found between x = 0.8125 and 0.6875. The absorption features in the high-energy range of ε(2)(ω) are related to critical points of the band structure. The transition energies for these van Hove singularities are determined and their bowing parameters are discussed.
authors.affiliation: Applied Physics Department, Institute of Engineering and Technology, M J P Rohilkhand University, Bareilly-243 006, India. drsudhirkumar.in@gmail.com
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: Suman
authors.initials: S
authors.lastname: Pandey
authors.forename: S K
authors.initials: SK
authors.lastname: Gupta
authors.forename: Tarun K
authors.initials: TK
authors.lastname: Maurya
authors.forename: P
authors.initials: P
authors.lastname: Schley
authors.forename: G
authors.initials: G
authors.lastname: Gobsch
authors.forename: R
authors.initials: R
authors.lastname: Goldhahn