Properties of edge states in a spin-triplet two-band superconductor

Abstract

Motivated by Sr2RuO4, the magnetic properties of edge states in a two-band spin-triplet superconductor with electronlike and holelike Fermi surfaces are investigated assuming chiral p-wave pairing symmetry. The two bands correspond to the α-β bands of Sr2RuO4 and are modeled within a tight-binding model including interorbital hybridization and spin-orbit coupling effects. Including superconductivity, the quasiparticle spectrum is determined by means of a self-consistent Bogoliubov–de Gennes calculation. While a full quasiparticle excitation gap appears in the bulk, gapless states form at the edges that produce spontaneous spin and/or charge currents. The spin current is the result of the specific band structure, while the charge current originates from the superconducting condensate. Together they induce a small spin polarization at the edge. Furthermore, onsite Coulomb repulsion is included to show that the edge states are unstable against the formation of a Stoner-type spin polarization of the edge states. Through spin-orbit coupling, the current- and the correlation-induced magnetism are coupled to the orientation of the chirality of the superconducting condensate. We speculate that this type of phenomenon could yield a compensation of the magnetic fields induced by currents and also explain the negative result in the recent experimental search for chiral edge currents.

Source-reported materials — not catalogue approval

Similar papers