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

Research output: Contribution to journalArticlepeer-review

Abstract

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
Volume34
Issue number19-20
DOIs
Publication statusPublished - 2020 Jul 20

Keywords

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

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Condensed Matter Physics

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