A quantum engine by pumping electrons in a nanojunction with a single gate and dynamic tunnel couplings to the leads

Abstract

We configure a source-channel-drain nanojunction to function as either a quantum pump or a quantum engine by dynamically varying the tunnel couplings to the leads and applying a time-dependent gate potential. The dynamics of the time-varying components follow an operating protocal in such a way that electrons are pumped, adiabatically or nonadiabatically, from the left lead, through the channel, and on to the right lead without a source-drain bias potential. We express the electron energy current flowing across the device in terms of nonequilibrium Green’s functions. These nonequilibrium Green’s functions are then expressed in terms of steady-state Green’s functions which are, in turn, expressed in terms of the equilibrium Green’s functions of
the free leads. The equilibrium Green’s functions are determined from the equation of motion of each free lead.