Dr. Suk Bum Chung
Department of Physics
Stanford Institute for Theoretical Physics

Topological superconductivity from half- metal: a new host for Majorana fermions

Abstract:

As a half-metal is spin-polarized at its Fermi level by definition, it was conventionally thought to have little proximity effect to an s-wave superconductor. Here we show that, with interface spin-orbit coupling, p_x+ip_y superconductivity without spin degeneracy is induced on the half-metal, and we give an estimate of its bulk energy gap. Therefore a single-band half-metal can give us a topological superconductor with a single chiral Majorana edge state. Our band calculation shows that the VTe surface on ZnTe substrate and the surface state of bulk insulator NaCoO₂ are single-band half- metals a wide range (~0.1eV) of Fermi energy and thus is a suitable candidate material.