Magnetic and topological properties of edge states in the multi-band superconductor Sr₂RuO₄

Motivated by spin-triplet superconductor Sr₂RuO₄, the magnetic and topological properties of the edge states are investigated by means of the ribbon-shaped model with three Fermi surfaces as electronlike, holelike and two-dimensional ones, which correspond to the α-β bands and γ band of Sr₂RuO₄ in the two-dimensional bulk system. While there exists a full quasiparticle excitation gap, the gapless edge states appear in the ribbon system, in which these edge states are topologically protected and produce the spin and charge currents. While spin current results from the spin-orbit interaction, the charge current appears even without the external magnetic field and originates from the time-reversal symmetry breaking in chiral p-wave superconducting condensate. The effect of the repulsive interaction gives rise to the spin-polarization near the edges due to the Stoner mechanism. The magnetization from the currents couples correlation-induced magnetism through the spin-orbit interaction, so that the orientation of both magnetization is uniquely determined. The net spontaneous magnetic field from the edge current is strongly reduced due to the compensation of magnetic fields induced by correlation effect. This obtained result may explain the negative result from the experimental searches for chiral edge currents.