Abstract
The influence of electronic many-body interactions, spin-orbit coupling, and thermal lattice vibrations on the electronic structure of lithium niobate is calculated from first principles. Self-energy calculations in the approximation show that the inclusion of self-consistency in the Green function and the screened Coulomb potential opens the band gap far stronger than found in previous calculations but slightly overestimates its actual value due to the neglect of excitonic effects in . A realistic frozen-lattice band gap of about 5.9 eV is obtained by combining hybrid density functional theory with the scheme. The renormalization of the band gap due to electron-phonon coupling, derived here using molecular dynamics as well as density functional perturbation theory, reduces this value by about 0.5 eV at room temperature. Spin-orbit coupling does not noticeably modify the fundamental gap but gives rise to a Rashba-like spin texture in the conduction band.
1 More- Received 19 August 2015
- Revised 1 February 2016
DOI:https://doi.org/10.1103/PhysRevB.93.075205
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