Intersubband electron interaction in 1D–2D junctions

It is shown that the electron transport through junctions between one-and a two-dimensional systems and through quantum point contacts is considerably affected by the interaction of electrons belonging to different subbands. The interaction mechanism is related to Friedel oscillations, which are produced by the electrons of the closed subbands even in smooth transitions. Because of the interaction with these oscillations, electrons of the open subbands experience a backscattering. The electron reflection coefficient has a sharp peak at the energy equal to the Fermi energy and may reach a value of about 0.1. This result allows one to explain a number of available experimental facts.