GENERAL SCIENTIFIC SUMMARY
Introduction and background. The generalized master equation has been used to describe the nonequilibrium evolution of a subsystem in contact with a larger reservoir. Originally, in the field of quantum optics it was applied to atoms in a radiation field. Here we use it to describe the time-evolution of a finite quantum wire that is put into contact with two external semi-infinite leads (the reservoirs) at different chemical potentials causing a nonequilibrium current to flow through the finite quantum wire (the system).

Main results. We show that by carefully selecting the electron states relevant to the transport located in energy around the chemical potential window we are able to describe the transport through a finite quantum wire with complex geometry in contact with broad leads with nontrivial bandstructure. We observe a partial current reflection as a manifestation of a quasi-bound state in an embedded well and the formation of a resonance state between an off-set potential hill and the boundary of the system.

Wider implications. We have a many-electron description of a time-dependent transport through an electron system on the nanometer scale in the non-Markovian limit where memory effects and correlations imposed on the system by the coupling to the leads are not neglected. The model reproduces many results known from scattering approach to transport, and it opens up the possibility to explore correlation effects in the weak coupling limit caused by the leads and the mutual Coulomb interaction between the electrons in the system.

73.63.Nm Quantum wires

71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)

73.21.Hb Quantum wires

Condensed matter: electrical, magnetic and optical

Surfaces, interfaces and thin films

Nanoscale science and low-D systems

Issue 11 (November 2009)

Received 3 July 2009

Published 4 November 2009