Disorder suppression and precise conductance quantization in constrictions of PbTe quantum wells -: art. no. 125332

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 thus far, we observe precise conductance quantization in 2e(2)/h units, despite of a 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.