Investigation of in-plane anisotropy of c-axis magnetoresistance for BiCh2-based layered superconductor NdO0.7F0.3BiS2

TL;DR

This study explores the in-plane anisotropy of c-axis magnetoresistance in NdO0.7F0.3BiS2, revealing four-fold symmetry in superconducting states and two-fold symmetry in normal states, highlighting structural influences on electronic properties.

Contribution

It provides the first detailed comparison of in-plane MR anisotropy between superconducting and normal states in NdO0.7F0.3BiS2, emphasizing the role of crystal symmetry and disorder.

Findings

Four-fold symmetric MR observed below Tc in superconducting state

Two-fold symmetric MR observed in normal state with small amplitude

Differences from LaO0.5F0.5BiSSe suggest structural disorder effects

Abstract

We have investigated the in-plane anisotropy of the c-axis magnetoresistance (MR) in both superconducting and normal states of single crystals of NdO0.7F0.3BiS2 under in-plane magnetic fields. In the superconducting states of NdO0.7F0.3BiS2, four-fold-symmetric in-plane anisotropy of the c-axis MR was observed below the superconducting transition temperature. Since the crystal structure of NdO0.7F0.3BiS2 is tetragonal, the rotational symmetry in the superconducting state is preserved in the present compound. This result is clearly different from the previous report observed in LaO0.5F0.5BiSSe single crystals, where the in-plane MR in the superconducting state shows two-fold symmetry. On the other hand, in the normal states of NdO0.7F0.3BiS2, two-fold symmetric MR with a small amplitude was observed. The possible origin of the two-fold-symmetric behavior was discussed with the presence of local structural disorder in the conducting plane of BiCh2-based compounds.