Appearance of the universal value e2/h of the zero-bias conductance in a Weyl semimetal-superconductor junction

Song-Bo Zhang; Fabrizio Dolcini; Daniel Breunig; Björn Trauzettel

doi:10.1103/PhysRevB.97.041116

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Appearance of the universal value e2/h of the zero-bias conductance in a Weyl semimetal-superconductor junction

Song-Bo Zhang, Fabrizio Dolcini, Daniel Breunig, Björn Trauzettel

DOI 10.1103/PhysRevB.97.041116 · Physical Review B

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Abstract

We study the differential conductance of a time-reversal symmetric Weyl semimetal-superconductor junction with an s-wave superconducting state. We find that there exists an extended regime where the zero-bias differential conductance acquires the universal value of e2/h per channel, independent of the pairing and chemical potentials on each side of the junction, due to a perfect cancellation of Andreev and normal reflection contributions. This universal conductance can be attributed to the interplay of the unique spin/orbital-momentum locking and s-wave pairing that couples Weyl nodes of the same chirality. We expect that the universal conductance can serve as a robust and distinct signature for time-reversal symmetric Weyl fermions and be observed in the recently discovered time-reversal symmetric Weyl semimetals.