Donor binding energies in multivalley semiconductors

Altarelli, M.; Hsu, Wei‐Chung; Sabatini, Riccardo

doi:10.1088/0022-3719/10/21/004

Cited by 34 publications

(10 citation statements)

References 16 publications

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“…Thus, Umklapp scattering terms from the periodic lattice potential are more important, as it is easier for reciprocal lattice vectors G to 'resonantly' match differences k − k between two momenta belonging to separate Brillouin zones. The inter-valley weights C G (k 0ν , k 0µ ) (µ = ν) with G = 0 are thus expected to be more significant, as direct pseudopotential calculations show 17,34 . Our solution is to include the full Bloch structure of the donor states: the list of the relevant weights 34 .…”

Section: Multi-valley Effective Mass Theory Of Donors In Gementioning

confidence: 99%

“…However, the theoretical understanding of Ge donors is not well developed: the most modern approaches to describing the electron orbital states date back to the '70s [15][16][17] , with a satisfactory theory still missing to date. Nonetheless, a detailed picture is crucial for deciding whether Ge-donor spins could make promising qubits, and for anticipating the most desirable regimes for spin manipulation in such devices.…”

Section: Introductionmentioning

confidence: 99%

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Quantum gates with donors in germanium

Pica

Lovett

2016

Phys. Rev. B

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The possibility of quantum computing with spins in germanium nanoscale transistors has recently attracted interest since it promises highly tuneable qubits that have encouraging coherence times. We here present the first complete theory of the orbital states of Ge donor electrons, and use it to show that Ge could have significant advantages over silicon in the implementation of a donor-based quantum processor architecture. We show that the stronger spin-orbit interaction and the larger electron donor wave functions for Ge donors allow for greater tuning of the single qubit energy than for those in Si crystals, thus enabling a large speedup of selective (local) quantum gates. Further, exchange coupling between neighboring donor qubits is shown to be much larger in Ge than in Si, and we show that this greatly relaxes the precision in donor placement needed for robust two-qubit gates. To do this we compare two statistical distributions for Ge:P and Si:P pair couplings, corresponding to realistic donor implantation misplacement, and find that the spin couplings in Ge:P have a 33% chance of being within an order of magnitude of the largest coupling, compared with only 10% for the Si:P donors. This allows fast, parallel and robust architectures for quantum computing with donors in Ge.

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Section: Multi-valley Effective Mass Theory Of Donors In Gementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantum gates with donors in germanium

Pica

Lovett

2016

Phys. Rev. B

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“…The coefficient C nm kY q determines the relative weight of intravalley and intervalley transitions. On using the approximation of Shindo-Altarelli [24,25] for the state jnY ki we get…”

Section: The Dielectric Functionmentioning

confidence: 99%

“…We shall limit our analysis of the dielectric function to the long wavelength limit (q 3 0) in the range of densities n % 10 15 to 10 20 cm À3 where an order of magnitude for b is given by (24). It can be seen that the ratio between the intervalley and intravalley contribution to (25) is of the order of 10 À5 to 10 À4 and becomes significant only for those values of q near to the valley separation $ 2DY $ 2 p D. The intravalley contribution to (25) is given by…”

Section: The Static Regimementioning

confidence: 99%

“…In Section 3 we have said that their contribution is negligible. To see this, we can write equation (25) as follows: where we have separated the intra and intervalley contributions. Since b a ( 1 and b r q % b r q 0 ) 1Y from the power series of both Fb a and Fb r , to the lowest order, we have the following Thomas-Fermi (TF) limit:…”

Section: The Overall Responsementioning

confidence: 99%

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Conduction Electron Gas Dielectric Function of Multivalley Semiconductors: An Application to Silicon

Liguori¹,

Ninno²,

Iadonisi³

1998

phys. stat. sol. (b)

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The dielectric function of multivalley conduction electron systems is studied taking into account both the intravalley and the intervalley matrix elements. A direct application is performed for the six-valley silicon case. It is shown that the dielectric function takes the form of a sum of Lindhardtype terms, each one related to a pair of valleys. Analytical approximations for the static and dynamical cases are proposed. It is shown that while in the static case the intervalley contributions are negligible, in the dynamical case they lead to composite plasma dispersion of acoustic type for q 3 0. New analytical approximate plasma dispersion formulae are presented and it is shown that the acoustic behavior can be interpreted within a two-component plasma model where to the intervalley contributions an effective mass lighter than the band mass is associated.

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Polarizabilities of Donors in Elemental Semiconductors (II)

Palaniyandi

1980

Physica Status Solidi (b)

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Using the multivalley effective mass equation and a variational method, an expression for the polarizability of donors in semiconductors is derived including the electron mass anisotropy in the Hamiltonian and using an improved trial function. Polarizability estimates of shallow donors in Si are made and these are compared with experimental results and the results of earlier calculations. The electron mass anisotropy contributes significantly to the polarizability values. Estimates of the polarizabilities of shallow donors in Ge are also presented.

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Donor binding energies in multivalley semiconductors

Cited by 34 publications

References 16 publications

Quantum gates with donors in germanium

Quantum gates with donors in germanium

Conduction Electron Gas Dielectric Function of Multivalley Semiconductors: An Application to Silicon

Polarizabilities of Donors in Elemental Semiconductors (II)

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