Physical properties and electronic structure of the two-gap superconductor V$_{2}$Ga$_{5}$

TL;DR

This study thoroughly investigates the physical properties and two-gap superconductivity of V2Ga5, revealing its critical temperature, pressure dependence, and electronic structure, supported by experimental and theoretical analyses.

Contribution

It provides the first comprehensive experimental and theoretical characterization of V2Ga5 as a phonon-mediated two-gap s-wave superconductor.

Findings

Superconducting transition at 3.5 K

Two superconducting gaps at Fermi surface points

Superconductivity suppressed linearly under pressure

Abstract

We present a thorough investigation of the physical properties and superconductivity of the binary intermetallic V2Ga5. Electrical resistivity and specific heat measurements show that V2Ga5 enters its superconducting state below Tsc = 3.5 K, with a critical field of Hc2,perp c(Hc2,para c) = 6.5(4.1) kOe. With H perp c, the peak effect was observed in resistivity measurements, indicating the ultrahigh quality of the single crystal studied. The resistivity measurements under high pressure reveal that the Tsc is suppressed linearly with pressure and reaches absolute zero around 20 GPa. Specific heat and muon spin relaxation measurements both indicate that the two-gap s-wave model best describes the superconductivity of V2Ga5. The spectra obtained from angle-resolved photoemission spectroscopy measurements suggest that two superconducting gaps open at the Fermi surface around the Z and {\Gamma} points. These results are verified by first-principles band structure calculations. We therefore conclude that V2Ga5 is a phonon-mediated two-gap s-wave superconductor