Gate-defined Quantum Point Contact in an InSb Two-dimensional Electron Gas

TL;DR

This paper demonstrates a gate-defined quantum point contact in an InSb 2DEG, revealing conductance quantization, subband structure, and Zeeman splitting with large g factors, advancing spintronic applications.

Contribution

It provides the first detailed characterization of a gate-defined quantum point contact in InSb 2DEG, including conductance quantization and g factor measurements.

Findings

Observation of well-defined conductance plateaus

Extraction of subband structure from finite-bias measurements

Measurement of large in-plane and out-of-plane g factors

Abstract

We investigate an electrostatically defined quantum point contact in a high-mobility InSb two-dimensional electron gas. Well-defined conductance plateaus are observed, and the subband structure of the quantum point contact is extracted from finite-bias measurements. The Zeeman splitting is measured in both in-plane and out-of-plane magnetic fields. We find an in-plane g factor $|g_{\parallel}^* | \approx$ 40. The out-of-plane g factor is measured to be $|g_{\perp}^* | \approx$ 50, which is close to the g factor in the bulk.