Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 57: Topological Semimetals III
TT 57.3: Talk
Wednesday, March 14, 2018, 10:30–10:45, A 053
Appearance of the universal value e2/h of the zero-bias conductance in a Weyl semimetal-superconductor junction — Songbo Zhang1, •Fabrizio Dolcini2, Daniel Breunig1, and Björn Trauzettel1 — 1Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany — 2Dipartimento di Scienza Applicata e Tecnologia del Politecnico di Torino, I-10129 Torino, Italy
We study the differential conductance of a time-reversal symmetric Weyl semimetal-superconductor (N-S) junction with an s-wave superconducting state. We find that there exists an accessible regime where the zero-bias differential conductance acquires the universal value e2/h per unit 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.