Superconductivity in La1-xSmxO0.5F0.5BiS2 (x = 0.2, 0.8) under hydrostatic pressure

TL;DR

This study explores how hydrostatic pressure affects superconductivity in La1-xSmxO0.5F0.5BiS2, revealing a significant Tc increase for x=0.2 and no change for x=0.8, with pressure reducing the normal state resistivity.

Contribution

It provides new insights into pressure-induced Tc enhancement and normal state resistivity suppression in samarium-doped LaO0.5F0.5BiS2 superconductors.

Findings

Tc increases over threefold at ~1.74 GPa for x=0.2

Tc decreases monotonously beyond the pressure peak

Normal state resistivity is significantly reduced under pressure

Abstract

We have investigated the pressure effect on the newly discovered samarium doped La1-xSmxO0.5F0.5BiS2 superconductors. More than threefold increase in Tc (10.3 K) is observed with external pressure (at ~1.74 GPa at a rate of 4.08 K/GPa)) for x = 0.2 composition. There is a concomitant large improvement in the quality of the superconducting transition. Beyond this pressure Tc decreases monotonously at the rate of -2.09 K/GPa. In the x = 0.8 sample, we do not observe any enhancement in Tc with application of pressure (up to 1.76 GPa). The semiconducting behavior observed in the normal state resistivity of both of the samples is significantly subdued with the application of pressure which, if interpreted invoking thermal activation process, implies that the activation energy gap of the carriers is significantly reduced with pressure. We believe these observations should generate further interest in the La1-xSmxO0.5F0.5BiS2 superconductors.