Giant critical current peak induced by pressure in kagome superconductor RbV$_{3}$Sb$_{5}$

TL;DR

This study investigates how applying pressure affects superconductivity in the kagome superconductor RbV3Sb5, revealing a giant peak in critical current near the suppression of charge-density waves, indicating complex interplay between competing orders.

Contribution

It demonstrates the use of self-field critical current measurements to probe pressure-induced changes in superconductivity and charge-density wave interactions in RbV3Sb5.

Findings

Critical current peaks near the suppression of charge-density waves.

Emergence of a weaker critical current peak within the CDW phase.

Superconducting transition temperature plateaus near the critical pressure.

Abstract

Superconductivity can coexist or compete with other orders such as magnetism or density waves. Optimizing superconductivity requires identifying competing orders that may disrupt Cooper pair coherence. Here, we use the self-field critical current ($I_{\rm c,sf}$) to probe pressure-tuned superconductivity in the kagome superconductor RbV$_3$Sb$_5$. As pressure destabilizes the charge-density wave (CDW) state, $I_{\rm c,sf}$ drastically enhances, peaking near the critical pressure where the CDW state is completely suppressed at zero temperature. Surprisingly, a weaker $I_{\rm c,sf}$ peak emerges within the CDW phase. Near the pressure of the weaker peak, the superconducting phase transition temperature shifts from an increasing trend with pressure to a near plateau. Our analysis suggests the possibility of a sudden change in the CDW pattern or a Lifshitz transition, highlighting the need for microscopic examinations of the CDW state for understanding the pressure evolution of superconductivity in RbV$_3$Sb$_5$.