Figure 1
Crystal structure of LaO0.5F0.5BiS2−xSex and electrical resistivity in the absence of a magnetic field for LaO0.5F0.5BiS2−xSex. (a) Crystal structure of LaO0.5F0.5BiS2−xSex with a space group of P4/nmm (No. 129). The crystal structure image is prepared by VESTA35. (b) Two BiCh2 layers and LaO blocking layer. The inversion symmetry is locally broken in the each BiCh2 layer. The symbol P in the LaO blocking layer denotes the global inversion centre for the LaO0.5F0.5BiS2−xSex system. The thicknesses of the BiCh2 and the blocking layers were evaluated as the length between the centres of the two atomics by structural analysis of powder X-ray diffraction. (c,d) Temperature dependence of the resistivity in the absence of a magnetic field for x = 0.22 (c) and 0.69 (d). The insets show the enlarged resistivity curves near the superconducting transition. The superconducting transition temperature, Tc is defined as the midpoint of the resistive transition and was observed at Tc = 3.2 K and 4.1 K.
