Chirality inversion of Majorana edge modes in a Fu-Kane heterostructure

Abstract

Fu and Kane have discovered that a topological insulator with induced s-wave superconductivity (gap ${\Delta }_0$, Fermi velocity $v_{\mathrm{F}}$, Fermi energy $\mu$) supports chiral Majorana modes propagating on the surface along the edge with a magnetic insulator. We show that the direction of motion of the Majorana fermions can be inverted by the counterflow of supercurrent, when the Cooper pair momentum along the boundary exceeds ${\Delta }_0^2/\mu v_{\mathrm{F}}$. The chirality inversion is signaled by a doubling of the thermal conductance of a channel parallel to the supercurrent. Moreover, the inverted edge can transport a nonzero electrical current, carried by a Dirac mode that appears when the Majorana mode switches chirality. The chirality inversion is a unique signature of Majorana fermions in a spinful topological superconductor: it does not exist for spinless chiral p-wave pairing.

References in corpus (4)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• A road to reality with topological superconductors
• Chirality sensitive effect on surface states in chiral p-wave superconductors
• Effect of charge renormalization on electric and thermo-electric transport along the vortex lattice of a Weyl superconductor