文章基本信息

标题：Possible pairing mechanism switching driven by structural symmetry breaking in BiS2-based layered superconductors
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作者：Aichi Yamashita ; Hidetomo Usui ; Kazuhisa Hoshi 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2021
卷号：11
期号：1
页码：230
DOI：10.1038/s41598-020-80544-2
出版社：Springer Nature
摘要：Abstract Investigation of isotope effects on superconducting transition temperature ( T c ) is one of the useful methods to examine whether electron–phonon interaction is essential for pairing mechanisms. The layered BiCh 2 -based (Ch: S, Se) superconductor family is a candidate for unconventional superconductors, because unconventional isotope effects have previously been observed in La(O,F)BiSSe and Bi 4 O 4 S 3 . In this study, we investigated the isotope effects of 32 S and 34 S in the high-pressure phase of (Sr,La)FBiS 2 , which has a monoclinic crystal structure and a higher T c of ~ 10 K under high pressures, and observed conventional-type isotope shifts in T c . The conventional-type isotope effects in the monoclinic phase of (Sr,La)FBiS 2 are different from the unconventional isotope effects observed in La(O,F)BiSSe and Bi 4 O 4 S 3 , which have a tetragonal structure. The obtained results suggest that the pairing mechanisms of BiCh 2 -based superconductors could be switched by a structural-symmetry change in the superconducting layers induced by pressure effects.