In donor qubit arrays, each electron is not confined to a specific donor: long-range Coulomb interactions enable changes in gate biases near one donor to modify the charge configurations of others. This nonlocal crosstalk arises not only from electrostatic effects but also from interactions that are strong across the donor array. Here we investigate the strong interaction-induced charge redistribution as a function of gate voltages in $2\times 2$ phosphorus donor arrays in silicon. We construct a multiorbital Hubbard model of the donor array, parametrized by density functional theory, atomic tight-binding, and effective-mass theory, and we solve this Hubbard model with the density matrix renormalization group. We find that an effective two-orbital subspace provides an accurate description at experimentally relevant donor separations, enabling tractable many-body calculations. An interaction-induced charge redistribution is discovered that is not detectable in total-charge stability diagrams and cannot be captured by noninteracting models. We show that these features are protected by same-symmetry correlation energies. The findings have deep implications for operating donor-array-based quantum technology hardware.

Close

PrevNext

View figure in article

• Point defects
• Spin qubits
• Doped semiconductors
• Quantum many-body systems
• Density functional theory
• Density matrix renormalization group
• Extended Hubbard model
• Tight-binding model