  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.
