Three Dimensional Control of Monolothic Atomic-Scale Devices in Silicon*

Building on work that has demonstrated the viability of using vertically separated gates in 3D monolithic phosphorus-doped-silicon (Si:P) devices to couple to single electron transistors [1] and nanowires [2], we will show how reducing the footprint of these epitaxial gates coupled with a novel alignment procedure can be used to finely tune the electrostatic potential in donor atom devices. In the fashion of electrostatically defined quantum dots, we can tune parameters such as qubit-reservoir tunnel rates and inter-qubit tunnel coupling, which were hitherto fixed by the exact dopant atom positions. This work opens up new avenues of investigation in atom based qubits including two-qubit exchange gates in a symmetric noise-suppression regime and tuneable couplings for analog quantum simulators.

[1] M. Koch et. al. (2019). Spin read-out in atomic qubits in an all-epitaxial three-dimensional transistor. Nature Nanotechnology, 14(2), 137–140.
[2] S.R. McKibbin et. al. (2013). Epitaxial top-gated atomic-scale silicon wire in a three-dimensional architecture. Nanotechnology, 24(4), 045303.