Hall Coefficient of Semimetals

A recently developed formula for the Hall coefficient [A. Auerbach, Phys. Rev. Lett. 121, 66601 (2018)] is applied to nodal line and Weyl semimetals (including graphene), spin-orbit split semiconductor bands in two three dimensions. The calculation reduces a ratio of equilibrium susceptibilities, where corrections are negligible at weak disorder. Deviations from Drude's inverse carrier density associated with band degeneracies, Fermi surface topology, interband scattering. Experiments which can measure these deviations proposed.