Multigap nodeless superconductivity in the Dirac intermetallic alloy V2Ga5 with one-dimensional vanadium chains

Abstract

Superconductors possessing diverse symmetry-enforced topological states have been a subject of intense interest as they are arguably one of the most feasible candidates to realize so-called topological superconductivity, a source of Majorana fermions that hold great promise for topological quantum computing. Here we study the low-lying quasiparticle excitations in the superconducting intermetallic alloy V2Ga5 by low-temperature heat capacity and ultra-low-temperature thermal conductivity measurements. It is found that its electronic specific heat can be fitted by either a d-wave gap or two s-wave gaps. However, the low-T thermal conductivity clearly points to the multiple nodeless energy gaps in its low-lying excitation spectrum. On the other hand, first-principles calculations reveal a multitude of topological fermions near the Fermi level, involving discrete Dirac nodes as well as Dirac nodal lines. These topological carriers, when condensed into Cooper pairs, provide a natural platform for achieving topologically nontrivial phases and possible Majorana fermions.

Source-reported materials — not catalogue approval

Similar papers