Conductance Quantization at zero magnetic field in InSb nanowires

TL;DR

This paper demonstrates conductance quantization at zero magnetic field in InSb nanowires by improving interfaces and environment, providing evidence for ballistic transport crucial for topological phases, and explores sub-band evolution under magnetic fields.

Contribution

It introduces improved fabrication techniques enabling zero-field conductance quantization and analyzes sub-band behavior in magnetic fields, advancing understanding of ballistic transport in nanowires.

Findings

Achieved conductance quantization at zero magnetic field.

Identified orbital degeneracy between sub-bands at high magnetic fields.

Enhanced nanowire-metal interface improves ballistic transport evidence.

Abstract

Ballistic electron transport is a key requirement for existence of a topological phase transition in proximitized InSb nanowires. However, measurements of quantized conductance as direct evidence of ballistic transport have so far been obscured due to the increased chance of backscattering in one dimensional nanowires. We show that by improving the nanowire-metal interface as well as the dielectric environment we can consistently achieve conductance quantization at zero magnetic field. Additionally, studying the sub-band evolution in a rotating magnetic field reveals an orbital degeneracy between the second and third sub-bands for perpendicular fields above 1T.