Physical properties and electronic structure of the two-gap superconductor V2Ga5

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,⊥c(Hc2,||c)=6.5(4.1) kOe. With H⊥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 indicate that the two-gap s-wave model best describes the superconductivity of V2Ga5. The bands near the Fermi level around the Z and Γ points are observed and analyzed by the angle-resolved photoemission spectroscopy measurements and first-principles band structure calculations. We therefore conclude that V2Ga5 is a phonon-mediated two-gap s-wave superconductor. Published by the American Physical Society 2024