Pressure cycle of superconducting Cs0.8Fe2Se2: a transport study

TL;DR

This study investigates how pressure affects the electrical resistivity and superconductivity of Cs0.8Fe2Se2, revealing that pressure suppresses Tc without restoring metallic behavior, and the resistivity hump is unrelated to superconductivity.

Contribution

First detailed pressure-dependent resistivity measurements of Cs0.8Fe2Se2, showing superconductivity suppression and resistivity behavior under pressure.

Findings

Resistivity decreases significantly under pressure.

Superconducting Tc drops around 8 GPa.

Resistivity hump persists despite pressure changes.

Abstract

We report measurements of the temperature and pressure dependence of the electrical resistivity of single crystalline iron-based chalcogenide Cs0.8Fe2Se2. In this material superconductivity Tc~30K develops from a normal state with extremely large resistivity. At ambient pressure a large "hump" in the resistivity is observed around 200K. Under pressure, the resistivity decreases by two orders of magnitude, concomitant with a sudden Tc suppression around p~8GPa. Even at 9GPa a metallic resistivity state is not recovered, and the {\rho}(T) "hump" is still detected. A comparison of the data measured upon increasing and decreasing the external pressure leads us to suggest that superconductivity is not related to this hump.