Department of Physics, Renmin University, Beijing, 100872, People's Republic of China.
Phys Rev Lett. 2012 Jul 20;109(3):037003. doi: 10.1103/PhysRevLett.109.037003.
We report a comprehensive angle-resolved photoemission spectroscopy study of the tridimensional electronic bands in the recently discovered Fe selenide superconductor ((Tl,Rb)(y)Fe(2-x)Se2 (T(c)=32 K). We determined the orbital characters and the k(z) dependence of the low energy electronic structure by tuning the polarization and the energy of the incident photons. We observed a small 3D electron Fermi surface pocket near the Brillouin zone center and a 2D like electron Fermi surface pocket near the zone boundary. The photon energy dependence, the polarization analysis and the local-density approximation calculations suggest a significant contribution from the Se 4p(z) and Fe 3d(xy) orbitals to the small electron pocket. We argue that the emergence of Se 4p(z) states might be the cause of the different magnetic properties between Fe chalcogenides and Fe pnictides.
我们报告了在最近发现的铁硒化物超导体（（Tl，Rb）（y）Fe（2-x）Se2（T（c）= 32 K）中三维电子能带的全角度分辨光发射谱研究。我们通过调节入射光子的偏振和能量来确定低能电子结构的轨道特征和 k（z）依赖性。我们在布里渊区中心附近观察到一个小的 3D 电子费米表面口袋，在区边界附近观察到一个二维类似的电子费米表面口袋。光子能量依赖性、偏振分析和局域密度近似计算表明，Se 4p（z）和 Fe 3d（xy）轨道对小电子口袋有重要贡献。我们认为，Se 4p（z）态的出现可能是 Fe 硫属化物和 Fe 磷化物之间不同磁性质的原因。
