Calculation of self-energy corrected band structure of rhombohedral LiNbO3

Abstract
The band structure of LiNbO3 in the rhombohedral structure has been calculated by a first-principles method. An approximate k-dependent and energy-dependent self-energy correction scheme is applied to the LDA result. It is shown that the band gap in LiNbO3 is approximately direct. The self energy correction enlarges the gap by 36% to 3.56 eV, in good agreement with measurement.