Diffusive and Ballistic Transport in Ultra-thin InSb Nanowire Devices Using a Few-layer-Graphene-AlOx Gate

TL;DR

This study demonstrates phase-coherent transport in ultra-thin InSb nanowire devices with a novel FLG-AlOx gating approach, advancing the development of topological quantum devices by addressing disorder effects.

Contribution

Introduces a new fabrication method with ultra-thin InSb nanowires and a FLG-AlOx gate, enabling phase-coherent transport measurements relevant for quantum computing.

Findings

Observation of conductance plateaus indicating quantized transport

Detection of Fabry-Pérot interference patterns

Potential for reducing disorder in quantum devices

Abstract

Quantum devices based on InSb nanowires (NWs) are a prime candidate system for realizing and exploring topologically-protected quantum states and for electrically-controlled spin-based qubits. The influence of disorder on achieving reliable topological regimes has been studied theoretically, highlighting the importance of optimizing both growth and nanofabrication. In this work we investigate both aspects. We developed InSb nanowires with ultra-thin diameters, as well as a new gating approach, involving few-layer graphene (FLG) and Atomic Layer Deposition (ALD)-grown AlOx. Low-temperature electronic transport measurements of these devices reveal conductance plateaus and Fabry-P\'erot interference, evidencing phase-coherent transport in the regime of few quantum modes. The approaches developed in this work could help mitigate the role of material and fabrication-induced disorder in semiconductor-based quantum devices.