We present some results of theoretical studies conducted on the roles played by contacts and junctions in electron transport in quantum wire systems. With experiments conducted on semiconductor quantum wires as motivation, we first present the results of a phenomenological model of a Tomonaga-Luttinger liquid quantum wire system (with 2DEG Fermi reservoirs) built to provide a qualitative understanding of the puzzling results observed by Yacoby et al. (PRL 77, 4612 (1996)) in cleaved-edge overgrowth quantum wires. We then present a study of three quantum wires (each with weak, repulsive inter-electron interactions) meeting at a junction characterised by a scattering matrix. We develop the RG equations for the elements of the scattering matrix and discuss the rich RG phase diagram of this system.

Université de Cologne