Atomistic modeling of dynamical quantum transport

Abstract

We present dynamical transport calculations based on a tight-binding approximation to adiabatic time-dependent density functional theory (TD-DFTB). The reduced device density matrix is propagated through the Liouville-von Neumann equation. For the model system, 1,4-benzenediol coupled to aluminum leads, we are able to confirm the equality of the steady state current resulting from a time-dependent calculation to a static calculation in the conventional Landauer framework. We also investigate the response of the junction subjected to alternating bias voltages with frequencies up to the optical regime. Here we can clearly identify capacitive behaviour of the molecular device and a significant resonant enhancement of the conductance. The results are interpreted using an analytical single level model comparing the device transmission and admittance. In order to aid future calculations under alternating bias, we shortly review the use of Fourier transform techniques to obtain the full frequency response of the device from a single current trace.

Submitted to special issue of pss (b), corrected typos in Eqs. 9/10/11

References in corpus (7)

• Time-dependent density-functional theory for open systems
• Dynamical corrections to the DFT-LDA electron conductance in nanoscale systems
• Resonant electron heating and molecular phonon cooling in single C${}_{60}$ junctions
• Incompleteness of the Landauer Formula for Electronic Transport
• First-principles quantum transport modeling of thermoelectricity in single-molecule nanojunctions with graphene nanoribbon electrodes
• Time-dependent versus static quantum transport simulations beyond linear response
• The Role of Bound States in Time-Dependent Quantum Transport