By envelope-function approximation, we computed the effect of confinement in spherical P-doped Si nanocrystals in a uniform electric field without adjustable parameters. Based on nanocrystal size, we can distinguish several regimes. For a radius R that is larger than Rt (Rt∼21 nm) the ground state is ionized at a critical electric field, Ecr, by tunneling from a 1s-like state, localized at the impurity, to a 2p-like state, localized to the well that is formed by the electric field and the potential barrier that is generated by the embedding matrix at the nanocrystal surface. For smaller nanocrystals, for which Rsp<R<Rt (Rsp∼7 nm), there is a range of electric fields in which the ground state is formed by the hybridization of the impurity states and surface-well states. Further, within this hybridization range, there is a value of the electric field at which the ground 1s-like state and the excited 2p0 state have the same hyperfine coupling. Based on these findings, we envisage a quantum computing scheme in which qubits shuttling relies on excited states when an electric field is applied.

By envelope-function approximation, we computed the effect of confinement in spherical P-doped Si nanocrystals in a uniform electric field without adjustable parameters. Based on nanocrystal size, we can distinguish several regimes. For a radius R that is larger than R(t) (R(t) similar to 21 nm) the ground state is ionized at a critical electric field, epsilon(cr), by tunneling from a 1s-like state, localized at the impurity, to a 2p-like state, localized to the well that is formed by the electric field and the potential barrier that is generated by the embedding matrix at the nanocrystal surface. For smaller nanocrystals, for which R(sp) < R < R(t) (R(sp) similar to 7 nm), there is a range of electric fields in which the ground state is formed by the hybridization of the impurity states and surface-well states. Further, within this hybridization range, there is a value of the electric field at which the ground 1s-like state and the excited 2p(0) state have the same hyperfine coupling. Based on these findings, we envisage a quantum computing scheme in which qubits shuttling relies on excited states when an electric field is applied.

Debernardi, A., Fanciulli, M. (2010). Stark effect of confined shallow levels in phosphorus-doped silicon nanocrystals. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 81(19), 195302 [10.1103/PhysRevB.81.195302].

Stark effect of confined shallow levels in phosphorus-doped silicon nanocrystals

FANCIULLI, MARCO
2010

Abstract

By envelope-function approximation, we computed the effect of confinement in spherical P-doped Si nanocrystals in a uniform electric field without adjustable parameters. Based on nanocrystal size, we can distinguish several regimes. For a radius R that is larger than R(t) (R(t) similar to 21 nm) the ground state is ionized at a critical electric field, epsilon(cr), by tunneling from a 1s-like state, localized at the impurity, to a 2p-like state, localized to the well that is formed by the electric field and the potential barrier that is generated by the embedding matrix at the nanocrystal surface. For smaller nanocrystals, for which R(sp) < R < R(t) (R(sp) similar to 7 nm), there is a range of electric fields in which the ground state is formed by the hybridization of the impurity states and surface-well states. Further, within this hybridization range, there is a value of the electric field at which the ground 1s-like state and the excited 2p(0) state have the same hyperfine coupling. Based on these findings, we envisage a quantum computing scheme in which qubits shuttling relies on excited states when an electric field is applied.
Articolo in rivista - Articolo scientifico
silicon nanocrystals, donors, hyperfine interaction
donors, silicon, hyperfine interaction, nanocrystals
English
4-mag-2010
81
19
195302
195302
none
Debernardi, A., Fanciulli, M. (2010). Stark effect of confined shallow levels in phosphorus-doped silicon nanocrystals. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 81(19), 195302 [10.1103/PhysRevB.81.195302].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/21725
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