Chiral response in lattice models of Weyl materials

E. V. Gorbar, V. A. Miransky, I. A. Shovkovy, P. O. Sukhachov

Published 2017-06-28Version 1

For a generic lattice Hamiltonian of the electron states in Weyl materials, we calculate analytically the chiral charge and current (valley polarization) densities in the first order in background electromagnetic and strain-induced pseudoelectromagnetic fields. We find that the chiral response induced by the fields is not topologically protected. While for the well-separated Fermi surfaces surrounding the individual Weyl nodes the current coincides almost exactly with the current of the chiral separation effect, there are clear deviations when the Fermi surfaces undergo the Lifshitz transition. In addition, although our calculations reproduce qualitatively the anomalous chiral Hall effect, the actual result for the conductivity depends on the definition of the chirality as well as on the parameters of the lattice model.