Investigation of superconducting properties and possible nematic superconductivity in self-doped BiCh2-based superconductor CeOBiS1.7Se0.3

We investigate the superconducting properties and possible nematic superconductivity of self-doped BiCh2-based (Ch: S, Se) superconductor CeOBiS1.7Se0.3 through the measurements of in-plane anisotropy of magnetoresistance. Single crystals of CeOBiS1.7Se0.3 were grown using a flux method. Single-crystal structural analysis revealed that the crystal structure at room temperature is tetragonal (P4/nmm). Bulk superconductivity with a transition temperature of 3.3 K was observed through electrical resistivity and magnetization measurements. Investigation of anisotropy of upper critical field suggested relatively low anisotropy in the crystal as compared to other BiCh2-based superconductors. In the superconducting states of CeOBiS1.7Se0.3, two-fold symmetric in-plane anisotropy of magnetoresistance was observed, which indicates the in-plane rotational symmetry breaking in the tetragonal structure and hence the possibility of nematic superconductivity in CeOBiS1.7Se0.3.