Charge Relaxation Resistances in Gated Graphene Nanoribbons

We investigate the charge relaxation resistances in a typical graphene nanoribbon FET (GNRFET). We show that the behavior of the charge relaxation resistances heavily depends on the exerted gate voltage and the structural details of the GNRFET. When there is 0 channel (blocked), 1 channel, and N channels in the GNR as tuned by the gate voltage, the equilibrium charge relaxation resistance is roughly 1, 1/2, and 1/2N of Sharvin-Imry contact resistance (h/2e²), respectively, whereas the nonequilibrium charge relaxation resistance is much smaller. Our results indicate that the charge relaxation resistances characterizing the information of dissipation, RC time and noise can be controlled by the gate voltage.