Time-Reversal Symmetry Breaking Superconductivity in Three-Dimensional Dirac Semimetallic Silicides

Abstract

Superconductors with broken time-reversal symmetry represent arguably one of the most promising venues for realizing highly sought-after topological superconductivity that is vital to fault-tolerant quantum computation. Here, by using extensive muon-spin relaxation and rotation measurements, we report that the isostructural silicide superconductors (Ta, Nb)OsSi spontaneously break time-reversal symmetry at the superconducting transition while surprisingly showing a fully-gapped superconductivity characteristic of conventional superconductors. The first-principles calculations show that (Ta, Nb)OsSi are three-dimensional Dirac semimetals protected by nonsymmorphic symmetries. Taking advantage of the exceptional low symmetry crystal structure of these materials, we have performed detailed theoretical calculations to establish that the superconducting ground state for both (Ta, Nb)OsSi is most likely a nonunitary triplet state.

arXiv comment7 pages, 4 figures

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Cited by in corpus (9)

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• Signature of point nodal superconductivity in the Dirac semimetal PdTe
• Proximity effect of time-reversal symmetry broken non-centrosymmetric superconductors
• Probing the superconducting gap structure of ScRuSi via $\mu$SR and first-principles calculations
• ZrOsSi: A $Z_2$ topological metal with a superconducting ground state
• Pair-mixing induced Time-reversal-breaking superconductivity
• Self-dual Maxwell-Chern-Simons solitons in a parity-invariant scenario
• Broken time-reversal symmetry detected by tunneling spectroscopy of superconducting Pd-doped CaAgP
• Nonequilibrium Green's function approach to multi-band Cooper-pair transport: linear magnetoresistance effect due to nonunitary superconductivity