San Jose, Pablo and Prada, Elsa and Kohler, Sigmund and Schomerus, Henning (2011) Single-parameter pumping in graphene. Physical review B, 84 (15): 155408. ISSN 1550-235X
Abstract
We propose a quantum pump mechanism based on the particular properties of graphene, namely chirality and bipolarity. The underlying physics is the excitation of evanescent modes entering a potential barrier from one lead, while those from the other lead do not reach the driving region. This induces a large nonequilibrium current with electrons stemming from a broad range of energies, in contrast to the narrow resonances that govern the corresponding effect in semiconductor heterostructures. Moreover, the pump mechanism in graphene turns out to be robust, with a simple parameter dependence, which is beneficial for applications. Numerical results from a Floquet scattering formalism are complemented with analytical solutions for small to moderate driving.