  We propose a method to electrically control electron spins in donor-based
qubits in silicon. By taking advantage of the hyperfine coupling difference
between a single-donor and a two-donor quantum dot, spin rotation can be driven
by inducing an electric dipole between them and applying an alternating
electric field generated by in-plane gates. These qubits can be coupled with
exchange interaction controlled by top detuning gates. The qubit device can be
fabricated deep in the silicon lattice with atomic precision by scanning
tunneling probe technique. We have combined a large-scale full band atomistic
tight-binding modeling approach with a time-dependent effective Hamiltonian
description, providing a design with quantitative guidelines.
