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

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 $p_{\mathrm{c}}$ ($1.4<p_{\mathrm{c}}<1.6$ GPa), while the superconducting transition temperature $T_{\mathrm{c}}$ is maximized. $T_{\mathrm{c}}$ 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.

intended for a special issue on vanadium-based kagome materials in Chinese Physics B, updated with additional measurements on a second sample