Edge Currents in Chiral Superfluids and Superconductors

Condensed Matter Seminars

Speaker: Wen Huang (McMaster and KITP)
Date & Time: October 13, 2015, 1:00 - 2:00
Location: Hennings 309
Local Contact: Marcel Franz
Intended Audience: Graduate

Cooper pairs in two-dimensional chiral superfluids and superconductors carry non-zero and quantized orbital angular momentum. This leads to non-trivial topological properties of these chiral phases, as manifested in the presence of protected gapless chiral edge modes. On intuitive grounds, spontaneous supercurrent should arise at the edges of these systems, although it must lack topological protection due to U(1) symmetry breaking. This talk will focus on our study of the edge current in these systems. I will show that, rather surprisingly, edge current vanishes identically for all chiral superfluids except chiral p-wave. Generalizing to chiral superconductors on a lattice, a non-p-wave state may support finite yet comparatively smaller current than that of a chiral p-wave. A detailed discussion will be given to the implications of these results for putative chiral superconductors, such as Sr2RuO4 and UPt3. I will also briefly mention a connection with the orbital angular momentum problem in regard to the A-phase of He-3.

Reference: WH, E. Taylor, and C. Kallin, PHYSICAL REVIEW B 90, 224519 (2014).