Europhys. Lett.
Volume 67, Number 1, July 2004
Page(s) 14 - 20
Section General
Published online 01 June 2004
Europhys. Lett., 67 (1) , pp. 14-20 (2004)
DOI: 10.1209/epl/i2004-10043-7

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

G. Stefanucci and C.-O. Almbladh

Department of Solid State Theory, Institute of Physics, Lund University Sölvegatan 14 A, 223 62 Lund, Sweden

(Received 30 January 2004; accepted in final form 29 April 2004)

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.

05.60.Gg - Quantum transport.
72.10.Bg - General formulation of transport theory.
85.30.Mn - Junction breakdown and tunneling devices (including resonance tunneling devices).

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