By the first-principles electronic structure calculations, we have studied electronic structures of FeSe monolayer and bilayer thin films on SrTiO3 (001) with SrO-termination or TiO2 termination. We find that both FeSe monolayer and bilayer on either termination behave like a slightly doped semiconductor and a collinear antiferromagnetic order on Fe ions. There is no substantial charge transfer between the FeSe layers and the substrate. FeSe is adhered to the SrTiO3 surface by a dipole-dipole interaction. The Fermi surface is mainly the contribution of Fe-3d orbitals. A valence band contributed mainly by the O-2p orbitals in the TiO2 layer is located slightly below the Fermi level, which can become conducting upon a small doping of holes.
@article{arxiv.1202.0538,
title = {Atomic and electronic structures of FeSe monolayer and bilayer thin films on SrTiO$_3$ (001): a first-principles study},
author = {Kai Liu and Zhong-Yi LU and Tao Xiang},
journal= {arXiv preprint arXiv:1202.0538},
year = {2012}
}