Prof. Manfred Sigrist (ETH Zurich, Switzerland)
"A closer look on some features of chiral superconductors"
Chiral superconductors receive much attention in the context of topological electronic phases. Their topological properties are characterized uniquely by a Chern number. The experimental identification of chiral superconductors is not entirely trivial as I try to convey in this talk. I will start with a brief overview on candidate materials: Sr2RuO4 - chiral p-wave symmetry, UPt3 , URu2Si2 , SrPtAs - chiral d-wave symmetry. The focus lies on two key features of chiral superconductors: edge currents and chiral domains which both could help in the identification of the pairing symmetry. Sr2RuO4 is the prime example to address complex connection of chiral quasi-particle edge states and edge currents as well as the features connected with chiral domains. A detailed analysis reveals that the spontaneous edge supercurrents behave in some cases quite counter intuitive and it will be shown why there is no unique connection between the Chern number and edge current. This kind of relation works, however, for the Righi-Leduc effect, which constitutes a quantized thermal Hall effect here. Chiral domains can lead to peculiar interference patterns in the Josephson effect. They may potentially play an important role for the critical current of chiral superconductors. The latter will also include a discussion of the chiral d-wave phase as may be realized in SrPtAs.