SHG spectroscopy of the surface states of a chiral Weyl semimetal*

Second harmonic generation (SHG) is an optical effect that has recently been extensively used to study the electronic band structure as well as lattice and electronic symmetry of various inversion-symmetry breaking solid state materials, including topological systems. Since the surface of any material is a locus of inversion symmetry breaking, SHG spectroscopy has traditionally been used to selectively probe the surface electronic properties of materials. We present an SHG study of a chiral Weyl semimetal as a function of incident photon energy to study SHG response deriving solely from the surface and discuss what our analysis of the nonlinear tensor elements reveals on the topological nature of the material.