Multiple-gap weak-coupling superconductivity in the full-Heusler compound TiPd2Ga

Abstract

Superconductivity was observed in the full-Heusler compound TiPd2Ga below 1.4 K. Polycrystalline samples of TiPd2Ga were prepared by the arc-melting method. TiPd2Ga adopts a centrosymmetric cubic structure with the space group Fm-3m. Electrical-resistivity and magnetic-susceptibility measurements reveal that TiPd2Ga is a type-II superconductor with a large Ginzburg-Landau parameter. The upper critical field μ0Hc2 of ∼2.28 T is slightly lower than the Bardeen-Cooper-Schrieffer Pauli limit (μ0HP=2.58 T) in this three-dimensional superconductor with inversion symmetry, suggesting conventional superconducting states. Thermodynamic and transport data evidence the multigap weak-coupling BCS regime of TiPd2Ga. In addition, we note that a charge density wave like transition lies at ∼90 K. First-principles calculations indicate that the Pd-4d and Ti-3d orbits dominate the states at the Fermi level (EF), showing that different electronic components induce the multiband characters. The flat band topology and van Hove singularity near EF contribute to the superconducting and charge instabilities in this system. The discovery of the first Ti-containing Heusler superconductor TiPd2Ga may benefit to make sense of the pairing mechanisms of Heusler-phase and other related intermetallic superconductors.

Source-reported materials — not catalogue approval

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