Time-dependent quantum transport: An exact formulation based on TDDFT

PACS. 72.10.Bg – General formulation of transport theory. PACS. 85.30.Mn – Junction breakdown and tunneling devices (including resonance tunneling devices). Abstract. – An exact theoretical framework based on Time Dependent Density Functional Theory (TDDFT) is proposed in order to deal with the time-dependent quantum transport in fully interacting systems. We use a partition-free approach by Cini in which the whole system is in equilibrium before an external electric field is switched on. Our theory includes the interactions between the leads and between the leads and the device. It is well suited for calculating measurable transient phenomena as well as a.c. and other time-dependent responses. We show that the steady-state current results from a dephasing mechanism provided the leads are macroscopic and the device is finite. In the d.c. case, we obtain a Landauer-like formula when the effective potential of TDDFT is uniform deep inside the electrodes. Introduction. – During the last decade, the experimental progress in the fabrication/ma-nipulation of nano-systems like quantum wires and dots has enhanced the interest in the theory of quantum transport. The Landauer-Büttiker formalism [1,2] applies to noninteracting