Observation of temperature-induced crossover to an orbital-selective mott phase in AxFe2-ySe2 (A=K, Rb) superconductors

M. Yi, D. H. Lu, R. Yu, S. C. Riggs, J. H. Chu, B. Lv, Z. K. Liu, M. Lu, Y. T. Cui, M. Hashimoto, S. K. Mo, Z. Hussain, C. W. Chu, I. R. Fisher, Q. Si, Z. X. Shen

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Abstract

Using angle-resolved photoemission spectroscopy, we observe the low-temperature state of the AxFe2-ySe2 (A=K, Rb) superconductors to exhibit an orbital-dependent renormalization of the bands near the Fermi level - the dxy bands heavily renormalized compared to the dxz/dyz bands. Upon raising the temperature to above 150 K, the system evolves into a state in which the dxy bands have depleted spectral weight while the dxz/dyz bands remain metallic. Combined with theoretical calculations, our observations can be consistently understood as a temperature-induced crossover from a metallic state at low temperatures to an orbital-selective Mott phase at high temperatures. Moreover, the fact that the superconducting state of A xFe2-ySe2 is near the boundary of such an orbital-selective Mott phase constrains the system to have sufficiently strong on-site Coulomb interactions and Hund's coupling, highlighting the nontrivial role of electron correlation in this family of iron-based superconductors.

Original languageEnglish
Article number067003
JournalPhysical review letters
Volume110
Issue number6
DOIs
Publication statusPublished - 2013 Feb 5

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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