Highly-robust reentrant superconductivity in CsV3Sb5 under pressure

TL;DR

This study reveals highly robust reentrant superconductivity in CsV3Sb5 under high pressure, with two distinct superconducting phases and significant electronic structure changes, highlighting pressure as a tool to tune topological and superconducting properties.

Contribution

It demonstrates the existence of two superconducting domes in CsV3Sb5 under pressure and links electronic structure modifications to reentrant superconductivity.

Findings

Superconducting transition temperature (Tc) peaks at 7.6 K and 5.2 K in two phases.

Pressure induces significant changes in electronic structure and phonon spectra.

Reentrant superconductivity is driven by electronic structure and electron-phonon coupling modifications.

Abstract

Here we present the superconducting property and structural stability of kagome CsV3Sb5 under in-situ high pressures. For the initial SC-I phase, its Tc is quickly enhanced from 3.5 K to 7.6 K and then totally suppressed at P~10 GPa. Further increasing the applied pressures, an SC-II phase emerges at P~15 GPa and persists up to 100 GPa. The Tc rapidly increases to the maximal value of 5.2 K at P=53.6 GPa and rather slowly decreases to 4.7 K at P=100 GPa. A two-dome-like variation of Tc in CsV3Sb5 is concluded here. The Raman measurements demonstrate that weakening of E2g model and strengthening of A1g model occur without phase transition as entering the SC-II phase, which is supported by the results of phonon spectra calculations. Electronic structure calculations reveal that exertion of pressure may bridge the gap of topological surface nontrivial states near EF, i. e. Z2 invariant. Meanwhile, it enlarges Fermi surface significantly, consistent with the increased carrier density. The findings here point out the change of electronic structure and strengthened electron-phonon coupling should be responsible for the pressure-induced reentrant SC.