Adiabatic quantum pumping in graphene with magnetic barriers

Abstract

We study an adiabatic quantum pump effect in a two terminal graphene device with two oscillating square electric barriers and a stationary magnetic barrier using the scattering matrix approach. The model employs the low-energy Dirac approximation and incorporates the possible existence of a finite band gap in graphene spectrum. We show that in this case valley-polarized and pure valley currents can be pumped due to the valley symmetry breaking. For a \delta-function magnetic barrier we present analytical expressions for bilinear total and valley pumping responses. These results are compared to numerical ones for a double \delta-function, a square and a triple square magnetic barriers.