Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Topological Semimetals II
TT 20.11: Vortrag
Montag, 12. März 2018, 17:45–18:00, A 053
Andreev reflection in time-reversal symmetric Weyl semimetals — •Jens Schulenborg1, Uli Zuelicke2, and Michele Governale2 — 1Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Göteborg, Sweden — 2School of Physical and Chemical Sciences and Alan MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University Of Wellington, New Zealand
The study of the unusual chiral properties of Weyl fermions in Weyl semimetals (WSM) has attracted enormous attention in the past decade. Most recently, reports[1,2] on simple WSM band structures with only the minimum number of Weyl nodes suggest that it might become possible to exploit the nontrivial spin-momentum locking directly through ballistic scattering. This can be useful for spectroscopy or spin-dependent quantum optics with electrons.
To explore this perspective, we theoretically study elastic Andreev reflection in a minimal model of a time-reversal symmetric WSM, at an interface between a normal and superconducting region with s-wave pairing. We show that without interface-related spin-mixing, the subgap reflection processes at the four Weyl cones completely decouple. This arguably simplest form of Andreev scattering in a time-reversal symmetric WSM can be described by a 3D analogue of graphene, with the key difference that the pseudospin becomes an effective, yet in principle accessible spin.
K. Koepernik et al., Phys. Rev. B 93, 201101 (2016)
I. Belopolski et al., Nat. Commun. 8, 942 (2017)