Kai Liu, Zhong-Yi LU, Tao Xiang
By the first-principles electronic structure calculations, we have studied
electronic structures of FeSe monolayer and bilayer thin films on SrTiO$_3$
(001) with SrO-termination or TiO$_2$ termination. We find that both FeSe
monolayer and bilayer on either termination behave like a slightly doped
semiconductor with a small band gap 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 SrTiO$_3$ 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 TiO$_2$ layer is
located slightly below the Fermi level, which can become conducting upon a
small doping of holes.
View original:
http://arxiv.org/abs/1202.0538
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