Generalized Master equation approach to mesoscopic time-dependent transport

TL;DR

This paper employs a generalized Master equation approach to model non-equilibrium, time-dependent electron transport in a quantum wire with modulated contacts, revealing transient behaviors and the influence of lead placement.

Contribution

It introduces a GME formalism for time-dependent transport in a lattice model, including Coulomb interactions, without relying on Markov or rotating wave approximations.

Findings

Transient currents can flow against bias in short time intervals.

Lead placement significantly affects current behavior.

Coulomb interactions are incorporated via exact diagonalization.

Abstract

We use a generalized Master equation (GME) formalism to describe the non-equilibrium time-dependent transport through a short quantum wire connected to semi-infinite biased leads. The contact strength between the leads and the wire are modulated by out-of-phase time-dependent functions which simulate a turnstile device. One lead is fixed at one end of the sample whereas the other lead has a variable placement. The system is described by a lattice model. We find that the currents in both leads depend on the placement of the second lead. In the rather small bias regime we obtain transient currents flowing against the bias for short time intervals. The GME is solved numerically in small time steps without resorting to the traditional Markov and rotating wave approximations. The Coulomb interaction between the electrons in the sample is included via the exact diagonalization method.