Phosphorus δ-doped silicon: mixed-atom pseudopotentials and dopant disorder effects

Carter, Damien J.; Marks, Nigel A.; Warschkow, Oliver; McKenzie, David R.

doi:10.1088/0957-4484/22/6/065701

Cited by 38 publications

(102 citation statements)

References 27 publications

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“…we calculate VS L ′ as the average difference between the two 1L From this we derive an L ′ valley splitting of 193 meV, which is almost twice the value obtained using the mixedatom approach. As noted previously in the context of Si:P δ-doping 17,18 the mixed-atom approach, for all its intuitive utility, tends to underestimate valley splittings. Figure 5(c) shows the band structure for the same 1/4 ML explicit-ordered dopant pattern, except that phosphorus is now used as the dopant.…”

Section: Explicit-dopants: Orderedmentioning

confidence: 65%

“…Density functional theory (DFT) calculations on δ-doped germanium are conducted by adapting the general approach previously applied to Si:P by ourselves [16][17][18] and others [19][20][21] to the specific requirements of Ge:P and Ge:As. All calculations are performed using the SIESTA software.…”

Section: Methodsmentioning

confidence: 99%

“…35). As in our previous work on silicon 17,18 we use two distinct approaches to represent the dopant distribution in the δ layer: mixed-atom doping based on the virtual crystal approximation 36,37 and explicit doping using discrete distributions of phosphorus, arsenic, and germanium atoms. Explicit doping is the more realistic and hence more accurate representation, however its use is associated with a number of technical complexities that we will address below.…”

Section: 34mentioning

confidence: 99%

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Electronic structure of phosphorus and arsenicδ-doped germanium

et al. 2013

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Density functional theory in the LDA+U approximation is used to calculate the electronic structure of germanium δ-doped with phosphorus and arsenic. We characterize the principal band minima of the two-dimensional electron gas created by δ-doping and their dependence on the dopant concentration. Populated first at low concentrations is a set of band minima at the perpendicular projection of the bulk conduction band minima at L into the (kx,ky) plane. At higher concentrations band minima at Γ and ∆ become involved. Valley splittings and effective masses are computed using an explicit-atom approach, taking into account the effects of disorder in the arrangement of dopant atoms in the δ plane.

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Section: Explicit-dopants: Orderedmentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: 34mentioning

confidence: 99%

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Electronic structure of phosphorus and arsenicδ-doped germanium

et al. 2013

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“…Tight-binding calculations have also been performed [26][27][28], including a calculation of the quadratic Stark coefficient of the hyperfine interaction which has reproduced experimentally measured values more accurately than effective mass theory [29]. Two-dimensional layers of dopants in silicon known as δ-layers have been described using density functional theory with compact atomic-orbital basis sets [30,31], and additional DFT studies [16,32] evaluated the use of mixed pseudopotentials, which treat the dopant and silicon atoms in the layer using the same core potential, and compared them to all-atom calculations. These DFT calculations and a number of additional calculations (see Ref.…”

Section: Introductionmentioning

confidence: 99%

“…Although some of this disagreement can be attributed to geometrical effects of dopant placement which we will not explore in detail (see instead Refs. [33] and [16]), the accuracy of the description of dopant electronic structure contributes to these discrepancies. Additionally, electrically detected magnetic resonance (EDMR) [34] has called into question a theoretical picture of the scattering of electrons in a two-dimensional electron gas (2DEG) from dopants in silicon [35,36].…”

Section: Introductionmentioning

confidence: 99%

Large-scale atomistic density functional theory calculations of phosphorus-doped silicon quantum bits

2013

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We present density functional theory calculations of phosphorus dopants in bulk silicon and of several properties relating to their use as spin qubits for quantum computation. Rather than a mixed pseudopotential or a Heitler-London approach, we have used an explicit treatment for the phosphorus donor and examined the detailed electronic structure of the system as a function of the isotropic doping fraction, including lattice relaxation due to the presence of the impurity. Doping electron densities (ρ doped − ρ bulk ) and spin densities (ρ ↑ − ρ ↓ ) are examined in order to study the properties of the dopant electron as a function of the isotropic doping fraction. Doping potentials (V doped − V bulk ) are also calculated for use in calculations of the scattering cross-sections of the phosphorus dopants, which are important in the understanding of electrically detected magnetic resonance experiments. We find that the electron density around the dopant leads to non-spherical features in the doping potentials, such as trigonal lobes in the (001) plane at energy scales of +12 eV near the nucleus and of -700 meV extending away from the dopants. These features are generally neglected in effective mass theory and will affect the coupling between the donor electron and the phosphorus nucleus. Our density functional calculations reveal detail in the densities and potentials of the dopants which are not evident in calculations that do not include explicit treatment of the phosphorus donor atom and relaxation of the crystal lattice. These details can also be used to parameterize tight-binding models for simulation of large-scale devices.

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Atom‐by‐Atom Fabrication of Single and Few Dopant Quantum Devices

Wyrick

Wang

Kashid

et al. 2019

Adv Funct Materials

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Atomically precise fabrication has an important role to play in developing atom-based electronic devices for use in quantum information processing, quantum materials research, and quantum sensing. Atom-by-atom fabrication has the potential to enable precise control over tunnel coupling, exchange coupling, on-site charging energies, and other key properties of basic devices needed for solid state quantum computing and analog quantum simulation. Using hydrogen-based scanning probe lithography, individual dopant atoms are deterministically placed relative to atomically aligned contacts and gates to build single electron transistors, single atom transistors, and gate-controlled quantum sensing devices. The key steps required to fabricate and demonstrate the essential building blocks needed for spin selective initialization/readout, and coherent quantum manipulation are described.

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Phosphorus δ-doped silicon: mixed-atom pseudopotentials and dopant disorder effects

Cited by 38 publications

References 27 publications

Electronic structure of phosphorus and arsenicδ-doped germanium

Electronic structure of phosphorus and arsenicδ-doped germanium

Large-scale atomistic density functional theory calculations of phosphorus-doped silicon quantum bits

Atom‐by‐Atom Fabrication of Single and Few Dopant Quantum Devices

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