Band structure of functional oxides by screened exchange and the weighted density approximation

Abstract

PACS 71.20.Mq, 71.20.Ps Most ab-initio calculations of the electronic structure use the local density approximation, which gives good structural data but severely under-estimates the band gaps of semiconductors and insulators. This paper presents calculations of the band structures of some important oxide semiconductors and insulators, using the screened exchange method and the weighted density approximation, which give improved band gaps. The methods are tested on diamond, Si, Ge, MgO, Al 2 O 3 , and SiO 2 and the main interest is for

Band structure calculations of CuAlO2, CuGaO2, CuInO2, and CuCrOGillen1, Robertson2 2011Phys. Rev. B

“…GGA, as well as the hybrid functionals B3LYP 23 and HSE 21,24,25 and also G 0 W 0 24,25 , predict the global conduction band minimum to be at the Γ point, with a rivaling minimum at the L point. A previous study using the sX-functional yielded the same result 26 , but underestimated the band gap due to using to strong screening of the Hartree-Fock exchange.…”

Behavior of hydrogen in wide band gap oxides

“…WDA has been implemented in CASTEP. 32 Our calculations use the total energy plane wave pseudopotential code CASTEP. 34 The atoms are presented by Vanderbilt ultrasoft pseudopotentials.…”

“…CdO has an indirect gap, with a valence band maximum away from ⌫. 32,43 Experimentally, the minimum gap is about 0.8 eV and the smallest direct gap is 2.3 eV. 37 However, the minimum gap is negative in GGA.…”

Band gap and Schottky barrier heights of multiferroic BiFeO3

“…22 Here, we calculate the electronic structure of BiFeO 3 using the screened exchange ͑sX͒ method. [23][24][25][26] This is a parameter-free, density-functional method of including an improved electronic exchange potential, but it is less expensive than GW. The sX method has been found to give good band gaps for many insulating oxides and semiconductors.…”