Two-fold symmetry of in-plane magnetoresistance anisotropy in the superconducting states of BiCh2-based LaO0.9F0.1BiSSe single crystal

TL;DR

This study investigates the in-plane magnetoresistance anisotropy in LaO0.9F0.1BiSSe single crystals, revealing a robust two-fold symmetry in superconducting states across different doping levels, similar to nematic superconductors.

Contribution

It demonstrates that in-plane symmetry breaking in BiCh2-based superconductors persists across varying electron doping levels, indicating a robust phenomenon.

Findings

Two-fold in-plane anisotropy observed in LaO0.9F0.1BiSSe.

Anisotropy similar to that in higher doping LaO0.5F0.5BiSSe.

Symmetry breaking is robust to carrier concentration.

Abstract

Recently, two-fold symmetric in-plane anisotropy of the superconducting properties have been observed in a single crystal of BiCh2-based (Ch: S, Se) layered superconductor LaO0.5F0.5BiSSe having a tetragonal (four-fold-symmetric) in-plane structure; the phenomena are very similar to those observed in nematic superconductors. To explore the origin of the two-fold symmetric anisotropy in the BiCh2-based system, we have investigated the electron-doping dependence on the anisotropy by examining the in-plane anisotropy of the magnetoresistance in the superconducting states for a single crystal of LaO0.9F0.1BiSSe under high magnetic fields up to 15 T. We observed a two-fold symmetry of in-plane anisotropy of magnetoresistance for LaO0.9F0.1BiSSe. The results obtained for LaO0.9F0.1BiSSe are quite similar to those observed for LaO0.5F0.5BiSSe, which has a higher electron doping concentration than LaO0.9F0.1BiSSe. Our present finding suggests that the emergence of the in-plane symmetry breaking in the superconducting state is robust to the carrier concentration in the series of LaO1-xFxBiSSe.