A Schottky top-gated two-dimensional electron system in a nuclear spin free Si/SiGe heterostructure

TL;DR

This paper demonstrates the creation of a high-mobility two-dimensional electron system in a nuclear spin-free Si/SiGe heterostructure with effective top-gate control, paving the way for quantum dot devices with minimized electron spin decoherence.

Contribution

It reports the first realization of a Schottky top-gated 2D electron system in nuclear spin-free Si/SiGe, enabling quantum information applications with reduced decoherence.

Findings

Achieved electron mobility of 18000 cm²/Vs at low temperature.

Demonstrated reliable electrostatic gating with palladium Schottky gates.

Established a foundation for quantum dot devices in nuclear spin-free environments.

Abstract

We report on the realization and top-gating of a two-dimensional electron system in a nuclear spin free environment using 28Si and 70Ge source material in molecular beam epitaxy. Electron spin decoherence is expected to be minimized in nuclear spin-free materials, making them promising hosts for solid-state based quantum information processing devices. The two-dimensional electron system exhibits a mobility of 18000 cm2/Vs at a sheet carrier density of 4.6E11 cm-2 at low temperatures. Feasibility of reliable gating is demonstrated by transport through split-gate structures realized with palladium Schottky top-gates which effectively control the two-dimensional electron system underneath. Our work forms the basis for the realization of an electrostatically defined quantum dot in a nuclear spin free environment.