Time-dependent density functional theory for quantum transport

TL;DR

This paper introduces an exact, first-principles approach combining time-dependent density functional theory with quantum dissipation to simulate transient electronic transport in nanodevices, demonstrated on a carbon nanotube system.

Contribution

It develops a formally exact and computationally practical framework for simulating time-dependent quantum transport from first principles, integrating DFT with dissipation theory.

Findings

Successfully simulates transient current in a carbon nanotube device

Analyzes computational cost and accuracy of proposed schemes

Demonstrates applicability to realistic nanoscopic electronic systems

Abstract

Based on our earlier works [Phys. Rev. B 75, 195127 (2007) & J. Chem. Phys. 128, 234703 (2008)], we propose a formally exact and numerically convenient approach to simulate time-dependent quantum transport from first-principles. The proposed approach combines time-dependent density functional theory with quantum dissipation theory, and results in a useful tool for studying transient dynamics of electronic systems. Within the proposed exact theoretical framework, we construct a number of practical schemes for simulating realistic systems such as nanoscopic electronic devices. Computational cost of each scheme is analyzed, with the expected level of accuracy discussed. As a demonstration, a simulation based on the adiabatic wide-band limit approximation scheme is carried out to characterize the transient current response of a carbon nanotube based electronic device under time-dependent external voltages.