Indiumoxide polymorphs from first principles: Quasiparticle electronic states
Abstract
The electronic structure of In_{2}O_{3} polymorphs is calculated from first principles using density functional theory (DFT) and manybody perturbation theory (MBPT). DFT calculations with a local exchangecorrelation (XC) functional give the relaxed atomic coordinates of the two stable polymorphs. Their electronic structure, i.e., the band structure and density of states, is studied within MBPT. The quasiparticle equation is solved in two steps. As the zeroth approximation for the XC selfenergy the nonlocal potential resulting from a HSE03 hybrid functional is used. In the sense of a selfconsistent procedure G_{0}W_{0} quasiparticle corrections are computed on top. The calculated direct quasiparticle gaps at Γ amount to 3.3eV (rhombohedral) and 3.1eV (cubic). The rhombohedral polymorph is found to exhibit a near degeneracy of the valenceband maxima at the Γ point and on the ΓL line, while the valenceband maximum of the cubic polymorph occurs near Γ . Interconduction band transitions are identified as possible origin of conflicting experimental reports, claiming a much larger difference between the direct and indirect gap. The results for gaps, d band positions, and density of states are compared with available experimental data.
 Publication:

Physical Review B
 Pub Date:
 April 2008
 DOI:
 10.1103/PhysRevB.77.155107
 Bibcode:
 2008PhRvB..77o5107F
 Keywords:

 61.50.Ah;
 71.15.Nc;
 71.20.b;
 71.15.Qe;
 Theory of crystal structure crystal symmetry;
 calculations and modeling;
 Total energy and cohesive energy calculations;
 Electron density of states and band structure of crystalline solids;
 Excited states: methodology