A solid-state quantum microscope for wavefunction control of an atom-based quantum dot device in silicon
Quantum states of atomic systems can be directly addressed using quantum optical microscopes. However, solid-state microscopy techniques cannot typically achieve both local measurements and control of the state due to their measurement mechanism or the presence of a globally conductive substrate that impedes local gate control. Here we report a solid-state quantum microscope that can control and locally probe the wavefunctions of atomic quantum dots in silicon. Our microscope consists of a scanning tunnelling microscope tip, source and gate electrodes defined on an insulating silicon substrate by subsurface antimony implantation and phosphorus dopants incorporated with atomic precision. In contrast to conventional semiconductor qubit devices, the macroscopic electrodes are fabricated before patterning the nanoscale elements. A light-assisted method is designed to make the substrate conductive to stabilize the microscope tip close to the quantum dots, before reversing to an insulator for local gating and spectroscopy. We show that the microscope can be used to tune and map the charge states of single and double quantum dots, as well as control the relative electrochemical potential between two dots.