“Zero modes” in a two-dimensional multivalley electron gas and magnetic susceptibility of graphite intercalation compounds

Abstract

In certain graphite intercalation compounds the energy spectrum is described by a (2+1)-dimensional Dirac Hamiltonian with a finite mass term. Therefore the system reveals the features of a parity anomaly, known in (2+1) QED. Although the contributions from two band extrema to the abnormal current cancel each other, the anomaly manifests itself as an additional absorption in the dynamic magnetic susceptibility.