Pressure-induced phase transition for single crystalline LaO0.5F0.5BiSe2

TL;DR

This study demonstrates a pressure-induced phase transition in LaO0.5F0.5BiSe2, leading to a higher superconducting transition temperature and reduced anisotropy, suggesting potential for further Tc enhancement under increased pressure.

Contribution

It reveals a pressure-induced phase transition and associated changes in superconducting properties in LaO0.5F0.5BiSe2, a novel insight into its pressure-dependent superconductivity.

Findings

High-Tc phase appears at 2.16 GPa

Maximum Tc observed at 6.7 K under 2.44 GPa

Anisotropy reduces from 20 to 9.3 in high-Tc phase

Abstract

We have demonstrated a pressure-induced phase transition from a low-Tc phase to a high-Tc phase in a single crystal of the superconductor LaO0.5F0.5BiSe2. The high-Tc phase appears at 2.16 GPa and the maximum superconducting transition temperature (Tc) is observed at 6.7 K under 2.44 GPa. Although the anisotropy ({\gamma}) for the low-Tc phase is estimated to be 20, it is reduced by around half (9.3) in the high-Tc phase. This tendency is the same for the BiS2 system. The Tc of LaO0.5F0.5BiSe2 has continued to increase up to the maximum pressure of this study (2.44 GPa). Therefore applied further pressure has the potential to induce a much higher Tc in this system.