| Autor: |
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 |
| Rok vydání: |
2012 |
| Zdroj: |
Physical review letters. 110(6) |
| ISSN: |
1079-7114 |
| Popis: |
Using angle-resolved photoemission spectroscopy, we observe the low-temperature state of the A(x)Fe(2-y)Se(2) (A=K, Rb) superconductors to exhibit an orbital-dependent renormalization of the bands near the Fermi level-the d(xy) bands heavily renormalized compared to the d(xz)/d(yz) bands. Upon raising the temperature to above 150 K, the system evolves into a state in which the d(xy) bands have depleted spectral weight while the d(xz)/d(yz) 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(x)Fe(2-y)Se(2) 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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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