Quantum oscillations in a hexagonal boron nitride-supported single crystalline InSb nanosheet

TL;DR

This study reports the first experimental observation of quantum oscillations in a free-standing InSb nanosheet supported on hBN, demonstrating high mobility and tunable electron properties for potential quantum device applications.

Contribution

First experimental demonstration of quantum oscillations in a free-standing InSb nanosheet with high mobility and tunable carrier density.

Findings

Electron mobility exceeds 18000 cm²V⁻¹s⁻¹

Observation of well-defined Shubnikov-de Haas oscillations

Extraction of electron effective mass and quantum lifetime

Abstract

A gated Hall-bar device is made from an epitaxially grown, free-standing InSb nanosheet on a hexagonal boron nitride (hBN) dielectric/graphite gate structure and the electron transport properties in the InSb nanosheet are studied by gate-transfer characteristic and magnetotransport measurements at low temperatures. The measurements show that the carriers in the InSb nanosheet are of electrons and the carrier density in the nanosheet can be highly efficiently tuned by the graphite gate. The mobility of the electrons in the InSb nanosheet is extracted from low-field magneotransport measurements and a value of the mobility exceeding ~18000 cm$^2$V$^{-1}$s$^{-1}$ is found. High-field magentotransport measurements show well-defined Shubnikov-de Haas (SdH) oscillations in the longitudinal resistance of the InSb nanosheet. Temperature-dependent measurements of the SdH oscillations are carried out and key transport parameters, including the electron effective mass m$^*$$\sim$0.028 m$_0$ and the quantum lifetime $\tau$$\sim$0.046 ps, in the InSb nanosheet are extracted. It is for the first time that such experimental measurements have been reported for a free-standing InSb nanosheet and the results obtained indicate that InSb nanosheet/hBN/graphite gate structures can be used to develop advanced quantum devices for novel physics studies and for quantum technology applications.