A dual-gate InSb nanosheet field-effect device is realized and is used to investigate the physical origin and the controllability of the spin–orbit interaction in a narrow bandgap semiconductor InSb nanosheet. We demonstrate that by applying a voltage over the dual gate, efficiently tuning of the spin–orbit interaction in the InSb nanosheet can be achieved. We also find the presence of an intrinsic spin–orbit interaction in the InSb nanosheet at zero dual-gate voltage and identify its physical origin as a build-in asymmetry in the device layer structure. Having a strong and controllable spin–orbit interaction in an InSb nanosheet could simplify the design and realization of spintronic deceives, spin-based quantum devices, and topological quantum devices.

Semiconductor InSb nanosheet/hexagonal boron nitride (hBN)/graphite trilayers are fabricated, and single- and double-gate devices made from the trilayers are realized and characterized. The InSb nanosheets employed in the trilayer devices are epitaxially grown, free-standing, zincblende crystals and are in micrometer lateral sizes. The hBN and graphite flakes are obtained by exfoliation. Each trilayer is made by successively stacking an InSb nanosheet on an hBN flake and on a graphite flake using a home-made alignment stacking/transfer setup. The fabricated single- and double-gate devices are characterized by electrical and/or magnetotransport measurements. In all these devices, the graphite and hBN flakes are employed as the bottom gates and the gate dielectrics. The measurements of a fabricated single bottom-gate field-effect device show that the InSb nanosheet in the device has an electron field-effect mobility of ~ 7300 cm2V-1s-1 and a low gate hysteresis of ~ 0.05 V at 1.9 K. The measurements of a double-gate Hall-bar device show that both the top and the bottom gate exhibit strong capacitive couplings to the InSb nanosheet channel and can thus tune the nanosheet channel conduction effectively. The electron Hall mobility in the InSb nanosheet of the Hall-bar device is extracted to be larger than 1.1 × 104 cm2V-1s-1 at a sheet electron density of ~ 6.1 × 1011 cm-2 and 1.9 K and, thus, the device exhibits well-defined Shubnikov-de Haas oscillations.