Single-electron tunneling through an asymmetrical tunnel barrier

Issues pertaining to single-electron tunneling through an asymmetrical tunnel barrier are discussed. A simple means of incorporating the change in the barrier shape accompanying a tunneling event into calculation of tunnel resistance is proposed. Simulation results show that directionality of tunneling through asymmetrical tunnel barriers is not as strong as reported previously, and that even an unphysical effect could arise if the barrier shape change is neglected.