Electric-field driven donor-based charge qubits in semiconductors

ORAL

Abstract

We theoretically investigate donor-based charge qubit operation driven by external electric fields [1]. We consider initially a single electron bound to a shallow-donor pair in GaAs: This system allows the basic physics of the problem to be presented. In the case of Si, heteropolar configurations such as P-Sb$^+$ 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 relative position of the donors. 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 valley interference does not prevent the coherent manipulation of donor-based charge qubits by external electric fields. We also discuss the effect of perturbations due to additional distant donors. [1] B. Koiller, X. Hu, and S. Das Sarma, Phys. Rev. B 73, 045319 (2006)

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Authors

  • Belita Koiller

    Instituto de Fisica, UFRJ, Rio de Janeiro, Brazil, Instituto de Fisica, Universidade Federal do Rio de Janeiro, Brazil

  • Xuedong Hu

    State University of New York at Buffalo, University at Buffalo, SUNY, Department of Physics, University of Buffalo, SUNY, University at Buffalo, University at Buffalo, SUNY, Buffalo, NY

  • Sankar Das Sarma

    Condensed Matter Theory Center, Physics Department, University of Maryland, Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA, Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742, University of Maryland, Condensed Matter Theory Center, University of Maryland, College Park, MD 20742-4111, USA, University of Maryland, College Park, CMTC, Department of Physics, University of Maryland, College Park, MD 20742, CMTC, Department of Physics, UMD, Maryland, Condensed Matter Theory Center, University of Maryland