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Electric field driven donor-based charge qubits in semiconductors

Belita Koiller·Xuedong Hu·S. Das Sarma
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Abstract

We investigate theoretically donor-based charge qubit operation driven by external electric fields. The basic physics of the problem is presented by considering a single electron bound to a shallow-donor pair in GaAs: This system is closely related to the homopolar molecular ion H_2^+. In the case of Si, heteropolar configurations such as PSb^+ pairs are also considered. For both homopolar and heteropolar pairs, the multivalley conduction band structure of Si leads to short-period oscillations of the tunnel-coupling strength as a function of the inter-donor relative position. However, for any fixed donor configuration, the response of the bound electron to a uniform electric field in Si is qualitatively very similar to the GaAs case, with no valley quantum interference-related effects, leading to the conclusion that electric field driven coherent manipulation of donor-based charge qubits is feasible in semiconductors.

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Belita Koiller, Xuedong Hu, S. Das Sarma. 2005-10-19. Electric field driven donor-based charge qubits in semiconductors. https://doi.org/10.1103/physrevb.73.045319

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