Extremely high upper critical field in BiCh2-based (Ch: S and Se) layered superconductor LaO0.5F0.5BiS2-xSex (x = 0.22 and 0.69)

Kazuhisa Hoshi; Ryosuke Kurihara; Yosuke Goto; Masashi Tokunaga; Yoshikazu Mizuguchi

doi:10.1038/s41598-021-04393-3

Extremely high upper critical field in BiCh₂-based (Ch: S and Se) layered superconductor LaO_0.5F_0.5BiS_2-xSe_x (x = 0.22 and 0.69)

Sci Rep. 2022 Jan 7;12(1):288. doi: 10.1038/s41598-021-04393-3.

Authors

Kazuhisa Hoshi¹, Ryosuke Kurihara², Yosuke Goto¹, Masashi Tokunaga², Yoshikazu Mizuguchi³

Affiliations

¹ Department of Physics, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan.
² The Institute for Solid-State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan.
³ Department of Physics, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan. mizugu@tmu.ac.jp.

Abstract

Centrosymmetric compounds with local inversion symmetry breaking have tremendously interesting and intriguing physical properties. In this study, we focus on a BiCh₂-based (Ch: S, Se) layered superconductor, as a system with local inversion asymmetry, because spin polarisation based on the Rashba-Dresselhaus-type spin-orbit coupling has been observed in centrosymmetric BiCh₂-based LaOBiS₂ systems, while the BiCh₂ layer lacks local inversion symmetry. Herein, we report the existence of extremely high in-plane upper critical fields in the BiCh₂-based system LaO_0.5F_0.5BiS_2-xSe_x (x = 0.22 and 0.69). The superconducting states are not completely suppressed by the applied magnetic fields with strengths up to 55 T. Thus, we consider that the in-plane upper critical field is enhanced by the local inversion symmetry breaking and its layered structure. Our study will open a new pathway for the discovery of superconductors that exhibit a high upper critical field by focusing on the local inversion symmetry breaking.

Abstract

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