Spin Filling in a Silicon Quantum Dot Array

NIST is using atomically precise fabrication to develop devices for use in quantum information processing. We are using hydrogen-based scanning probe lithography for deterministic placement of individual dopant atoms with atomically aligned gates to fabricate arrayed few-donor devices for analog quantum simulation research. Understanding electron configurations and transport in small arrays is critical to simulating larger systems and exploring the huge parameter space of the Fermi-Hubbard model.

In this talk, we show STM-fabrication of a strongly tunnel-coupled 3x3 dot array in which electrons are fully delocalized across the sites. Each electron added to the array is indicated by a well-defined Coulomb peak. We extract the magnetic field dependence of the electron chemical potential and electron addition energy from which we determine the “Hund’s rule” for electron filling for an array. Using an extended Hubbard model, we simulate the spin/charge occupation, the spatial distribution of the many-body states and the electron addition energy spectrum.