First-principle calculations of the dielectric function of zinc-blende andwurtzite InN

Abstract

The imaginary part of the dielectric function of zinc-blende and wurtziteInN has been calculated using a full-potential linearized augmented planewave method. We show that the exchange potential of Engel and Vosko givesan insulating ground state for both structures. The real part of thedielectric function has been obtained from the Kramers-Kronig dispersionrelations, assuming a quasi-particle band-gap correction according toBechstedt and Del Sole. We have found that it is necessary to have a goodaccount of the band gap in order to derive the low-frequency opticalproperties. We present the longitudinal as well as the transversecomponents in wurtzite InN, showing that the anisotropy is small.