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arXiv · 0910.1675

A nonequilibrium theory for transient transport dynamics in nanostructures via the Feynman-Vernon influence functional approach

Jinshuang Jin·Matisse W. Y. Tu·Wei-Min Zhang·YiJing Yan
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Abstract

In this paper, we develop a nonequilibrium theory for transient electron transport dynamics in nanostructures based on the Feynman-Vernon influence functional approach. We extend our previous work on the exact master equation describing the non-Markovian electron dynamics in the double dot [Phys. Rev. B78, 235311 (2008)] to the nanostructures in which the energy levels of the central region, the couplings to the leads and the external biases applied to leads are all time-dependent. We then derive nonperturbatively the exact transient current in terms of the reduced density matrix within the same framework. This provides an exact non-linear response theory for quantum transport processes with back-reaction effect from the contacts, including the non-Markovian quantum relaxation and dephasing, being fully taken into account. The nonequilibrium steady-state transport theory based on the Schwinger-Keldysh nonequilibrium Green function technique can be recovered as a long time limit. For a simple application, we present the analytical and numerical results of transient dynamics for the resonance tunneling nanoscale device with a Lorentzian-type spectral density and ac bias voltages, where the non-Markovian memory structure and non-linear response to the bias voltages in transport processes are demonstrated.

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Jinshuang Jin, Matisse W. Y. Tu, Wei-Min Zhang, YiJing Yan. 2009-12-03. A nonequilibrium theory for transient transport dynamics in nanostructures via the Feynman-Vernon influence functional approach. https://doi.org/10.1088/1367-2630%2F12%2F8%2F083013

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