||Two distinct superconducting pairing states divided by the nematic end point in FeSe1−xSx
Hanaguri, Tetsuo ,
Iwaya, Katsuya ,
Kohsaka, Yuhki ,
Machida, Tadashi ,
Watashige, Tatsuya ,
Kasahara, Shigeru ,
Shibauchi, TakasadaMatsuda, Yuji
2018-05-02 , American Association for the Advancement of Science (AAAS)
「電子液晶」が超伝導に与える影響を直接観測 --高温超伝導を理解する手がかり--. 京都大学プレスリリース. 2018-05-29.
Unconventional superconductivity often competes or coexists with other electronic orders. In iron-based superconductors, a central issue has been the relationship between superconductivity and electronic nematicity, spontaneous breaking of the lattice rotational symmetry. Using spectroscopic-imaging scanning tunneling microscopy, we simultaneously investigated the electronic structure and the superconducting gap in FeSe1−xSx, where the nematicity diminishes above the nematic end point (NEP) at x = 0.17. The nematic band structure appears as anisotropic quasiparticle-interference patterns that gradually become isotropic with increasing x without anomalies at the NEP. By contrast, the superconducting gap, which is intact in the nematic phase, discontinuously shrinks above the NEP. This implies that the presence or absence of nematicity results in two distinct pairing states, whereas the pairing interaction is insensitive to the strength of nematicity.