Reversible tuning of superconductivity in pressurized qausi-one-dimensional A2Cr3As3 (A=K and Rb)

TL;DR

This study investigates how applying hydrostatic and uniaxial pressure affects superconductivity in A2Cr3As3 compounds, revealing reversible suppression of Tc linked to structural parameters, with potential implications for tuning superconductivity.

Contribution

It provides the first detailed pressure-temperature phase diagram for A2Cr3As3, demonstrating reversible tuning of Tc and identifying structural factors influencing superconductivity.

Findings

Pressure suppresses Tc in A2Cr3As3 compounds.

Uniaxial pressure is more effective than hydrostatic pressure.

Tc fully recovers after pressure release.

Abstract

In-situ hydrostatic and uniaxial high pressure studies were performed on recently discovered CrAs-based qausi-one-dimensional superconductors A2Cr3As3 (A=K and Rb). The established Pressure-Temperature phase diagram in this study clearly demonstrates that either hydrostatic pressure or uniaxial pressure globally suppresses the superconducting transition temperature (Tc), and the latter is more effective than the former. Interestingly, in the same hydrostatic pressure environment, the suppressing rate of Tc in Rb2Cr3As3 is nearly twice as that of K2Cr3As3. Significantly, the reduced Tc in these superconductors can fully recover to its ambient-pressure value after the applied pressure is entirely released. Our results suggest that the bonding distance and angle between Cr-Cr in the Cr3As3 chains are the key factor in determining Tc and that the optimal lattice for superconductivity is hosted in the pristine K2Cr3As3.