Three-dimensionality and orbital characters of Fermi surface in (Tl,Rb)$_y$Fe$_{2-x}$Se$_2$

Z. -H. Liu; P. Richard; N. Xu; G. Xu; Y. Li; X. -C. Fang; L. -L. Jia; G. -F. Chen; D. -M. Wang; J. -B. He; T. Qian; J. -P. Hu; H. Ding; S. -C. Wang

doi:10.1103/physrevlett.109.037003

arXiv · 1202.6417

Three-dimensionality and orbital characters of Fermi surface in (Tl,Rb)$_y$Fe$_{2-x}$Se$_2$

Z. -H. Liu·P. Richard·N. Xu·G. Xu·Y. Li·X. -C. Fang·L. -L. Jia·G. -F. Chen·D. -M. Wang·J. -B. He·T. Qian·J. -P. Hu·H. Ding·S. -C. Wang

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Abstract

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$_{2-x}$Se$_2$ ($T_c=32$ 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 4$p_z$ and Fe 3$d_{xy}$ orbitals to the small electron pocket. We argue that the emergence of Se 4$p_z$ states might be the cause of the different magnetic properties between Fe chalcogenides and Fe pnictides.

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Z. -H. Liu, P. Richard, N. Xu, G. Xu, Y. Li, X. -C. Fang, L. -L. Jia, G. -F. Chen, D. -M. Wang, J. -B. He, T. Qian, J. -P. Hu, H. Ding, S. -C. Wang. 2012-02-29. Three-dimensionality and orbital characters of Fermi surface in (Tl,Rb)$_y$Fe$_{2-x}$Se$_2$. https://doi.org/10.1103/physrevlett.109.037003

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