Multi-state current switching by voltage controlled coupling of crossed graphene nanoribbons

Abstract

The interlayer transport between two semi-infinite crossed graphene nanoribbons (GNRs) is governed by the quantum interference between the standing waves of the individual GNRs. An external bias applied between the GNRs controls the wavelength and hence the relative phase of these standing waves. Sweeping the applied bias results in multiple constructive and destructive interference conditions. The oscillatory nature of the voltage controlled interference gives rise to an oscillatory current-voltage response with multiple negative differential resistance regions. The period of oscillation is inversely proportional to the length of the finite ends of the GNRs. Quantum interference is explicitly shown to be the physical mechanism controlling the interlayer current by direct evaluation of the interlayer matrix element using analytical expressions for the wavefunctions.