Electronic Structure Properties in the Nematic Phases of FeSe
LIANG Yi1, WU Xian-Xin1, HU Jiang-Ping1,2,3**
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190 2Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA 5Collaborative Innovation Center of Quantum Matter, Beijing 100875
Abstract：We investigate the electronic structures of FeSe in the presence of different possible orders and spin-orbit coupling (SOC). It is found that only the ferro-orbital order (FO) and the collinear antiferro-magnetism (C-AFM) can simultaneously induce splittings at Γ and M. Bicollinear antiferro-magnetism (B-AFM) and SOC have very similar band structures on Γ–M near the Fermi level. The temperature T insensitive splitting at Γ and the T-dependent splitting at M observed in recent experiments can be explained by the d-wave bond nematic (dBN) order together with SOC. The recent observed Dirac cones and their T-dependence in FeSe thin films can also be well explained by the dBN order together with the band renormalization. Their thickness- and cobalt-doping-dependent behaviors are the consequences of electron doping and reduction of Se height. All these suggest that the nematic order in the FeSe system is the dBN order.
2015, Vol. 32 
