Topological superconducting phase and Majorana fermions in half-metal/superconductor heterostructures

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 two atomic layers of VTe or CrO2 is a single-band half-metal for a wide range (similar to 0.1 eV) of Fermi energy and thus is a suitable candidate material.