Proximity-induced superconductivity and Andreev reflection on the surface of nodal Weyl semimetals

Abstract In nodel Dirac semimetals the bulk conduction and valence bands touch along a line, typically a ring. One of the key properties of nodal Dirac semimetals is to have drumhead surface states, i.e. , surface states with a very large effective mass. In the presence of certain types of spin-rotation symmetry breaking perturbations the Dirac ring splits into two Weyl rings. In this work, we study the superconducting pairing induced via the proximity effect to the surface of nodal Weyl semimetals. We find how the tunneling to the surface affects the symmetry of the proximity-induced superconducting pairing. We then calculate the Andreev reflection and show that it can be used to probe the drumhead states.