Evolution of superconductivity and charge order in pressurized RbV$_3$Sb$_5$

TL;DR

This study investigates how applying pressure affects charge order and superconductivity in RbV$_3$Sb$_5$, revealing a complex phase diagram with two superconducting domes and their relation to resistance anomalies.

Contribution

It provides the first detailed pressure-dependent phase diagram of RbV$_3$Sb$_5$, showing a second superconducting dome linked to high-pressure resistance anomalies.

Findings

Charge order is suppressed at modest pressures.

Superconducting transition temperature peaks near critical pressure.

A second superconducting dome appears at higher pressures.

Abstract

The kagome metals $A$V$_3$Sb$_5$ ($A=$ K, Rb, Cs) under ambient pressure exhibit an unusual charge order, from which superconductivity emerges. In this work, by applying hydrostatic pressure using a liquid pressure medium and carrying out electrical resistance measurements for RbV$_3$Sb$_5$, we find the charge order becomes suppressed under a modest pressure $p_{\rm c}$ ($1.4<p_{\rm c}<1.6$ GPa), while the superconducting transition temperature $T_{\rm c}$ is maximized. $T_{\rm c}$ is then gradually weakened with further increase of pressure and reaches a minimum around 14.3 GPa, before exhibiting another maximum around 22.8 GPa, signifying the presence of a second superconducting dome. Distinct normal state resistance anomalies are found to be associated with the second superconducting dome, similar to KV$_3$Sb$_5$. Our findings point to qualitatively similar temperature-pressure phase diagrams in KV$_3$Sb$_5$ and RbV$_3$Sb$_5$, and suggest a close link between the second superconducting dome and the high-pressure resistance anomalies.