Time-dependent electronic transport properties of nano-devices with dynamic components

Authors

Eduardo Cuansing ⋅ PH Department of Electrical and Computer Engineering, National University of Singapore
Gengchiau Liang ⋅ SG Department of Electrical and Computer Engineering, National University of Singapore
Jian-Sheng Wang ⋅ SG Department of Physics and Centre for Computational Science and Engineering, National University of Singapore

Abstract

We formulate a time-dependent nonequilibrium Green’s function ap- proach to study the transport properties of many-body quantum systems containing time-varying components. We derive an expression for the time-dependent current, in terms of two-time nonequilibrium Green’s functions, that is numerically exact, i.e., the formula includes all terms in the Dyson series expansion. The first system we study is two-leads system where the interleads coupling is switched on dynamically. When the switch-on is abrupt, we find the transient current initially overshoots the expected steady-state value, oscillates, and then decays as a power-law to settle to a steady-state value. The power-law parameters depend on the values of the applied bias voltage, strength of the couplings, and the speed of the switch-on. The other system we study is a transistor-like system consisting of a linear chain with a time-varying gate potential acting on the channel. The system reacts to the dynamic gate potential with a relaxation time that depends on the strength of the couplings between sites in the system.

Downloads

Issue

2012: Proceedings of the 30th Samahang Pisika ng Pilipinas Physics Congress

Article ID

SPP2012-1B-1

Section

Condensed Matter Physics

Published

2012-10-22

How to Cite

[1]

E Cuansing, G Liang, and J-S Wang, Time-dependent electronic transport properties of nano-devices with dynamic components, Proceedings of the Samahang Pisika ng Pilipinas 30, SPP2012-1B-1 (2012). URL: https://proceedings.spp-online.org/article/view/SPP2012-1B-1.