Electronic phase diagram of Fe 1 + y Te 1 - X Se x revealed by magnetotransport measurements

T. Watanabe, T. Otsuka, S. Hagisawa, Y. Koshika, S. Adachi, T. Usui, N. Sasaki, S. Sasaki, S. Yamaguchi, Y. Uezono, Y. Nakanishi, M. Yoshizawa, S. Kimura

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1 Citation (Scopus)


Among the Fe-based superconductors, Fe1+yTe1-xSex is unique in that its crystal structure is the simplest and the electron correlation level is the strongest, and thus it is important to investigate the doping (x)-temperature (T) phase diagram of this system. However, inevitably incorporated excess Fe currently prevents the establishment of the true phase diagram. We overcome the aforementioned significant problem via developing a new annealing method termed as Te-annealing wherein single crystals are annealed under Te vapor. Specifically, we conducted various magnetotransport measurements on Te-annealed superconducting Fe1+yTe1-xSex. We observed that crossover from the incoherent to the coherent electronic state and opening of the pseudogap occurs at high temperatures (≈150 K for x = 0.2). This is accompanied by a more substantial pseudogap and the emergence of a phase with a multi-band nature at lower temperatures (below ≈ 50 K for x = 0.2) before superconductivity sets in. Based on the results, the third type electronic phase diagram in Fe-based high-Tc superconductors is revealed.

Original languageEnglish
Article number2040051
JournalModern Physics Letters B
Issue number19-20
Publication statusPublished - 2020 Jul 20


  • Fe-based superconductors
  • Te-annealing
  • electronic phase diagram
  • excess iron
  • incoherent to coherent crossover
  • magnetotransport measurements


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