Impurity-induced Anomalous Thermal Hall Effect in Chiral Superconductors
Vuditwat Ngampruetikorn and J. A. Sauls
- Address: Center for Applied Physics & Superconducting Technologies,
Department of Physics, Northwestern University, Evanston, IL 60208
- Date: December 1, 2019
Physical Review B (to be submitted) (2022)
We report theoretical results for the electronic contribution to thermal and electrical transport for chiral superconductors belonging to even or odd-parity E1 and E2 representations of the tetragonal and hexagonal point groups. Chiral superconductors exhibit novel transport properties that depend on the topology of the order parameter, topology of the Fermi surface, the spectrum of bulk and edge Fermionic excitations, and the structure of the impurity potential. In the case of electronic heat transport, impurities induce an anomalous (zero-field) thermal Hall conductivity that is easily orders of magnitude larger than the quantized edge contribution. The effect originates from branch-conversion scattering of Bogoliubov quasiparticles by the chiral order parameter, induced by potential scattering. The former transfers angular momentum between the condensate and the excitations that transport heat. The anomalous thermal Hall conductivity is shown to depend to the structure of the electron-impurity potential, as well as the winding number, ν, of the chiral order parameter, ∆(p)=|∆(p)| eiνϕp. The results provide quantitative formulae for interpreting heat transport experiments seeking to identify broken T and P symmetries, as well as the topology of the order parameter for chiral superconductors.
- Comment: 13 pages, 6 figures