Conductance quantization was measured in submicron constrictions of PbTe, patterned into narrow,12 nm wide quantum wells deposited between Pb0.92Eu0.08Te barriers. Because the quantum confinement imposed by the barriers is much stronger than the lateral one, the one-dimensional electron energy level structure is very similar to that usually met in constrictions of AlGaAs/GaAs heterostructures. However, in contrast to any other system studied so far, we observe precise conductance quantization in 2e2/h units, {\it despite of significant amount of charged defects in the vicinity of the constriction}. We show that such extraordinary results is a consequence of the paraelectric properties of PbTe, namely, the suppression of long-range tails of the Coulomb potentials due to the huge dielectric constant.
@article{arxiv.cond-mat/0506756,
title = {Disorder suppression and precise conductance quantization in constrictions of PbTe quantum wells},
author = {G. Grabecki and J. Wrobel and T. Dietl and E. Janik and M. Aleszkiewicz and E. Papis and E. Kaminska and A. Piotrowska and G. Springholz and G. Bauer},
journal= {arXiv preprint arXiv:cond-mat/0506756},
year = {2009}
}