Quantized magnetic confinement in quantum wires

A. Tarasov, S. Hugger, Hengyi Xu, M. Cerchez, T. Heinzel, I. V. Zozoulenko, U. Gasser-Szerer, D. Reuter, A. D. Wieck

Published 2009-07-10Version 1

Ballistic quantum wires are exposed to longitudinal profiles of perpendicular magnetic fields composed of a spike (magnetic barrier) and a homogeneous part. An asymmetric magnetoconductance peak as a function of the homogeneous magnetic field is found, comprising quantized conductance steps in the interval where the homogeneous magnetic field and the magnetic barrier have identical polarities, and a characteristic shoulder with several resonances in the interval of opposite polarities. The observations are interpreted in terms of inhomogeneous diamagnetic shifts of the quantum wire modes leading to magnetic confinement.