Experimental observation of incoherent-coherent crossover and orbital-dependent band renormalization in iron chalcogenide superconductors

Z. K. Liu, M. Yi, Y. Zhang, J. Hu, R. Yu, J. X. Zhu, R. H. He, Y. L. Chen, M. Hashimoto, R. G. Moore, S. K. Mo, Z. Hussain, Q. Si, Z. Q. Mao, D. H. Lu, Z. X. Shen

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Abstract

The level of electronic correlation has been one of the key questions in understanding the nature of superconductivity. Among the iron-based superconductors, the iron chalcogenide family exhibits the strongest electron correlations. To gauge the correlation strength, we performed a systematic angle-resolved photoemission spectroscopy study on the iron chalcogenide series Fe1+ySexTe1-x (0<x<0.59), a model system with the simplest structure. Our measurement reveals an incoherent-to-coherent crossover in the electronic structure as the selenium ratio increases and the system evolves from a weakly localized to a more itinerant state. Furthermore, we found that the effective mass of bands dominated by the dxy orbital character significantly decreases with increasing selenium ratio, as compared to the dxz/dyz orbital-dominated bands. The orbital-dependent change in the correlation level agrees with theoretical calculations on the band structure renormalization, and may help to understand the onset of superconductivity in Fe1+ySexTe1-x.

Original languageEnglish (US)
Article number235138
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number23
DOIs
StatePublished - Dec 22 2015

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Liu, Z. K., Yi, M., Zhang, Y., Hu, J., Yu, R., Zhu, J. X., He, R. H., Chen, Y. L., Hashimoto, M., Moore, R. G., Mo, S. K., Hussain, Z., Si, Q., Mao, Z. Q., Lu, D. H., & Shen, Z. X. (2015). Experimental observation of incoherent-coherent crossover and orbital-dependent band renormalization in iron chalcogenide superconductors. Physical Review B - Condensed Matter and Materials Physics, 92(23), [235138]. https://doi.org/10.1103/PhysRevB.92.235138