Delay of terminal current in systems with abruptly changed Hamiltonian

Publication date: Available online 24 January 2019Source: Physics Letters AAuthor(s): Mou Yang, Xian-Jin Ran, Bo Su, Rui-Qiang WangAbstractThe current response for the parameter change of a mesoscopic system is a practical issue for future's circuit design. Nowadays most considered cases are varied types of bias modulation, while the effect of change of conductor Hamiltonian is seldom addressed. In this paper, we investigate the response of ballistic transport induced by a sudden change of the conductor Hamiltonian. We formulize the terminal current in language of non-equilibrium Green's function. Our method is applied to one-dimensional tight-binding chains and we find that the terminal current has a delay to the Hamiltonian change. The amount of delay is not determined by the velocity of incident electrons in the bias window, but depends on the tight-binding hopping energy γ. The delay of current response at the detecting point away from where the Hamiltonian changes is Cγ−1, where C is a constant independent of the system.

Source: Physics Letters A - January 25, 2019 Category: Physics Source Type: research