Nematic quantum critical point without magnetism in FeSe1-xSx superconductors

Suguru Hosoi, Kohei Matsuura, Kousuke Ishida, Hao Wang, Yuta Mizukami, Tatsuya Watashige, Shigeru Kasahara, Yuji Matsuda, Takasada Shibauchi

Research output: Contribution to journalArticlepeer-review

138 Citations (Scopus)

Abstract

In most unconventional superconductors, the importance of antiferromagnetic fluctuations is widely acknowledged. In addition, cuprate and iron-pnictide high-temperature superconductors often exhibit unidirectional (nematic) electronic correlations, including stripe and orbital orders, whose fluctuations may also play a key role for electron pairing. In these materials, however, such nematic correlations are intertwined with antiferromagnetic or charge orders, preventing the identification of the essential role of nematic fluctuations. This calls for new materials having only nematicity without competing or coexisting orders. Here we report systematic elastoresistance measurements in FeSe1-xSx superconductors, which, unlike other iron-based families, exhibit an electronic nematic order without accompanying antiferromagnetic order. We find that the nematic transition temperature decreases with sulfur content x; whereas, the nematic fluctuations are strongly enhanced. Near x ≈0.17, the nematic susceptibility diverges toward absolute zero, revealing a nematic quantum critical point. The obtained phase diagram for the nematic and superconducting states highlights FeSe1-xSx as a unique nonmagnetic system suitable for studying the impact of nematicity on superconductivity.

Original languageEnglish
Pages (from-to)8139-8143
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number29
DOIs
Publication statusPublished - Jul 19 2016
Externally publishedYes

Keywords

  • Electronic nematicity
  • Iron-based superconductors
  • Nematic susceptibility
  • Quantum critical point
  • Unconventional superconductivity

ASJC Scopus subject areas

  • General

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