Ballistic PbTe Nanowire Devices

TL;DR

This paper reports the development of ballistic PbTe nanowire devices with quantized conductance at zero magnetic field, indicating reduced disorder and potential for Majorana and spin-orbit studies.

Contribution

Introduction of ballistic PbTe nanowire devices grown via SAG, achieving zero-field quantized conductance and valley degeneracy lifting, advancing nanowire quality for topological applications.

Findings

Observation of quantized conductance plateaus at zero magnetic field

Demonstration of reduced disorder in SAG-grown PbTe nanowires

Valley degeneracy lifting in PbTe nanowire devices

Abstract

Disorder is the primary obstacle in current Majorana nanowire experiments. Reducing disorder or achieving ballistic transport is thus of paramount importance. In clean and ballistic nanowire devices, quantized conductance is expected with plateau quality serving as a benchmark for disorder assessment. Here, we introduce ballistic PbTe nanowire devices grown using the selective-area-growth (SAG) technique. Quantized conductance plateaus in units of $2e^2/h$ are observed at zero magnetic field. This observation represents an advancement in diminishing disorder within SAG nanowires, as none of the previously studied SAG nanowires (InSb or InAs) exhibit zero-field ballistic transport. Notably, the plateau values indicate that the ubiquitous valley degeneracy in PbTe is lifted in nanowire devices. This degeneracy lifting addresses an additional concern in the pursuit of Majorana realization. Moreover, these ballistic PbTe nanowires may enable the search for clean signatures of the spin-orbit helical gap in future devices.