1208.0503 (Roland Gillen et al.)

Electronic structure of Lanthanide oxides by hybrid density functionals    [PDF]

Roland Gillen, Stewart J. Clark, John Robertson

The band structures of CeO2 and the lanthanide sesquioxides (Ln2O3, with Ln=La,...,Lu) have been calculated by the three hybrid functionals HSE03, HSE06 and sX-LDA. These describe the strongly correlated f-electrons of the oxides as well as or better than the recently reported G0W0@LDA+U results, and yield the correct band gaps and trends. The main band gap between the oxygen 2p states and lanthanide 5d states is nearly independent of the lanthanide and the minimum gap is controlled by the energies of the 4f states with respect to these band edges. The experimentally observed periodicity of band gaps for Ln2O3 arises from a decline of the f level energies across the lanthanide series. The sX-LDA method is found to be slightly better than HSE at predicting the 4f energies and thus the band gaps.

View original: http://arxiv.org/abs/1208.0503