Quantized Andreev conductance in semiconductor nanowires

TL;DR

This paper reports the observation of quantized Andreev conductance in PbTe-based hybrid nanowires, demonstrating low-disorder transport regimes that are promising for Majorana fermion research.

Contribution

It presents the first observation of quantized Andreev conductance in PbTe nanowires, highlighting their low disorder and potential for topological quantum computing.

Findings

Quantized conductance observed at 4e^2/h in Andreev transport.

Normal-state conductance quantized at 2e^2/h.

PbTe nanowires exhibit minimal mode mixing, unlike III-V nanowires.

Abstract

Clean one-dimensional electron systems can exhibit quantized conductance. The plateau conductance doubles if the transport is dominated by Andreev reflection. Here, we report quantized conductance observed in both Andreev and normal-state transports in PbTe-Pb and PbTe-In hybrid nanowires. The Andreev plateau is observed at $4e^2/h$, twice of the normal plateau value of $2e^2/h$. In comparison, Andreev conductance in the best-optimized III-V nanowires is non-quantized due to mode-mixing induced dips (a disorder effect), despite the quantization of normal-state transport. The negligible mode mixing in PbTe hybrids indicates an unprecedented low-disorder transport regime for nanowire devices, beneficial for Majorana researches.