Hyperfine Stark effect of shallow donors in silicon

Abstract

We present a complete theoretical treatment of Stark effects in doped silicon, whose predictions are supported by experimental measurements. A multi-valley effective mass theory, dealing non-perturbatively with valley-orbit interactions induced by a donor-dependent central cell potential, allows us to obtain a very reliable picture of the donor wave function within a relatively simple framework. Variational optimization of the 1s donor binding energies calculated with a new trial wave function, in a pseudopotential with two fitting parameters, allows an accurate match of the experimentally determined donor energy levels, while the correct limiting behavior for the electronic density, both close to and far from each impurity nucleus, is captured by fitting the measured contact hyperfine coupling between the donor nuclear and electron spin. We go on to include an external uniform electric field in order to model Stark physics: With no extra ad hoc parameters, variational minimization of the complete donor ground energy allows a quantitative description of the field-induced reduction of electronic density at each impurity nucleus. Detailed comparisons with experimental values for the shifts of the contact hyperfine coupling reveal very close agreement for all the donors measured (P, As, Sb and Bi). Finally, we estimate field ionization thresholds for the donor ground states, thus setting upper limits to the gate manipulation times for single qubit operations in Kane-like architectures: the Si:Bi system is shown to allow for A gates as fast as around 10 MHz.

11 pages, 6 figures

References in corpus (6)

• Solid state quantum memory using the 31P nuclear spin
• Room temperature quantum bit storage exceeding 39 minutes using ionized donors in 28-silicon
• Stark Tuning of Donor Electron Spins in Silicon
• Bismuth in silicon qubits: the role of EPR cancellation resonances
• External field control of donor electron exchange at the Si/SiO2 interface
• Conditional control of donor nuclear spins in silicon using Stark shifts

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• Anisotropic Stark Effect and Electric-Field Noise Suppression for Phosphorus Donor Qubits in Silicon
• Quadrupolar interactions between acceptor pairs in p-doped semiconductors
• Towards visualisation of central-cell-effects in scanning-tunnelling-microscope images of subsurface dopant qubits in silicon
• Heitler-London model for acceptor-acceptor interactions in doped semiconductors
• Qubit guidelines for solid-state spin defects