Pressure-induced phase transition inLa1−xSmxO0.5F0.5BiS

Abstract

Electrical resistivity measurements on La1−xSmxO0.5F0.5BiS2 (x = 0.1, 0.3, 0.6, 0.8) have been performed under applied pressures up to 2.6 GPa from 2 K to room temperature. The superconducting transition temperature Tc of each sample significantly increases at a Sm-concentration dependent pressure Pt, indicating a pressure-induced phase transition from a low-Tc to a high-Tc phase. At ambient pressure, Tc increases dramatically from 2.8 K at x = 0.1 to 5.4 K at x = 0.8; however, the Tc values at P > Pt decrease slightly with x and Pt shifts to higher pressures with Sm substitution. In the normal state, semiconducting-like behavior is suppressed and metallic conduction is induced with increasing pressure in all of the samples. These results suggest that the pressure dependence of Tc for the BiS2-based superconductors is related to the lattice parameters at ambient pressure and enable us to estimate the evolution of Tc for SmO0.5F0.5BiS2 under pressure.

The effective increase in atomic scale disorder by doping and superconductivity in Ca3Rh4Sn13

“…Electrical resistivity ρ at ambient pressure and magnetic fields up to 9 T was investigated by a conventional four-point ac technique using a quantum design physical properties measurement system (PPMS). Measurements of ρ under pressure were performed in a piston-cylinder clamped cell (for details, see [26,27]).…”

Anomalous Transport Properties in BiS2-based Superconductors LnO1−xFxBiS2 (Ln = Nd, La-Sm)

“…14) Furthermore, the semiconducting behavior of ρ(T ) at ambient pressure is suppressed by applying high pressure to LaO 1−x F x BiS 2 and La 1−y Sm y O 0.5 F 0.5 BiS 2 . 11,15) For NdO 1−x F x BiS 2 , it was reported that ρ(T ) for x = 0.3 exhibits metallic behavior, as well as that for x ∼ 0.5, [16][17][18][19][20] indicating that ρ(T ) is more metallic in NdO 1−x F x BiS 2 than in LaO 1−x F x BiS 2 . This tendency has been considered to be related to the variation of the packing density in the BiS 2 layers, which is caused by the difference in the ionic radius between La and Nd atoms (the so-called in-plane chemical pressure).…”

Evolution of Anisotropic Displacement Parameters and Superconductivity with Chemical Pressure in BiS2-Based REO0.5F0.5BiS2 (RE = La, Ce, Pr, and Nd)

“…In addition, the observed temperature dependence of the electrical resistivity was not metallic-like; it showed a weakly localized behavior in LaO1-xFxBiS2, although band calculations suggested that the electron-doped LaO1-xFxBiS2 should be metal [4,5,12]. These results suggested that the doped electrons were localized by the effect of structural disorder.In order to induce bulk superconductivity in LaO1-xFxBiS2, high pressure effects can be employed.The application of an external pressure induces bulk superconductivity with a Tc of ~10 K [13][14][15]. In addition, samples annealed under a high pressure (~2 GPa) also exhibit bulk superconductivity with a…”