Physical properties and electronic structure of the two-gap superconductor V_{2}Ga_{5}

Abstract

We present a thorough investigation of the physical properties and superconductivity of the binary intermetallic V_{2}Ga_{5}. Electrical resistivity and specific heat measurements show that V_{2}Ga_{5} enters its superconducting state below T_{sc}= 3.5 K, with a critical field of H_{c2,⊥c}(H_{c2,||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 T_{sc} 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 V_{2}Ga_{5}. 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 V_{2}Ga_{5} is a phonon-mediated two-gap s-wave superconductor.