Transient dynamics of non-interacting electrons in the channel of a nanotransistor with a time-varying gate potential

Abstract

We derive expressions for the time-dependent electron current and electron energy current in a nanotransistor where a time-varying gate potential is impinging on the channel. The currents are written in terms of the two-time nonequilibrium Green’s functions. As a specific implementation, we determine the currents in a device with a 3-site channel. Interestingly, the electron energy current vanishes at the center of the channel. At the left and right edges of the channel the energy currents are changing in time in an asymmetric fashion, with the gate potential directly affecting only the right edge. This result has direct implications on heating in a nanotransistor, i.e., that heat will show up at the left and right edges of the channel where contact to the source and drain electrodes occur.