Conductance of submicron constrictions of PbTe:Bi was studied up to 8T and between 4.2K and 50mK. The structures were fabricated by electron beam lithography and chemical etching of high--electron mobility films grown by MBE on BaF_2. In the moderately strong magnetic fields perpendicular to the current, B>1T, the conductance shows accurate quantization in the units of 1e^2/h as a function of the side-gate voltage. In the absence of the field, a temperature-independent step structure, with an average step height approx. 1e^2/h, is observed. It is suggested that such a quantization may reflect the lifting of the Kramers degeneracy by the exchange interaction among the electrons, effective despite a large dielectric constant of bulk PbTe.
@article{arxiv.cond-mat/9906178,
title = {Quantum ballistic transport in constrictions of n-PbTe},
author = {G. Grabecki and J. Wrobel and T. Dietl and K. Byczuk and E. Papis and E. Kaminska and A. Piotrowska and G. Springholz and M. Pinczolits and G. Bauer},
journal= {arXiv preprint arXiv:cond-mat/9906178},
year = {2009}
}