Electromagnetic control of valley splitting in ideal and disordered Si quantum dots

@article{Hosseinkhani2020ElectromagneticCO,
  title={Electromagnetic control of valley splitting in ideal and disordered Si quantum dots},
  author={Amin Hosseinkhani and Guido Burkard},
  journal={arXiv: Mesoscale and Nanoscale Physics},
  year={2020}
}
In silicon spin qubits, the valley splitting must be tuned far away from the qubit Zeeman splitting to prevent fast qubit relaxation. In this work, we study in detail how the valley splitting depends on the electric and magnetic fields as well as the quantum dot geometry for both ideal and disordered Si/SiGe interfaces. We theoretically model a realistic electrostatically defined quantum dot and find the exact ground and excited states for the out-of-plane electron motion. This enables us to… 

Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power

Hole spin qubits in planar Ge heterostructures are one of the frontrunner platforms for scalable quantum computers. In these systems, the spin-orbit interactions permit efficient all-electric qubit

Modelling of planar germanium hole qubits in electric and magnetic fields

Hole-based spin qubits in strained planar germanium quantum wells have received considerable attention due to their favourable properties and remarkable experimental progress. The sizeable spin-orbit

Blueprint of a scalable spin qubit shuttle device for coherent mid-range qubit transfer in disordered Si/SiGe/SiO$_2$

Silicon spin qubits stand out due to their very long coherence times, compatibility with industrial fabrication, and prospect to integrate classical control electronics. To achieve a truly scalable

On-demand electrical control of spin qubits

Will Gilbert,1, ∗ Tuomo Tanttu,1, ∗ Wee Han Lim,1 MengKe Feng,1 Jonathan Y. Huang,1 Jesus D. Cifuentes,1 Santiago Serrano,1 Philip Y. Mai,1 Ross C. C. Leon,1 Christopher C. Escott,1 Kohei M. Itoh,2

Impact of the valley orbit coupling on exchange gate for spin qubits in silicon

The mixing of conduction band valleys plays a critical role in determining electronic spectrum and dynamics in a silicon nanostructure. Here, we investigate theoretically how valley–orbit coupling

SiGe quantum wells with oscillating Ge concentrations for quantum dot qubits

Large-scale arrays of quantum-dot spin qubits in Si/SiGe quantum wells require large or tunable energy splittings of the valley states associated with degenerate conduction band minima. Existing

Valley splittings in Si/SiGe quantum dots with a germanium spike in the silicon well

Silicon-germanium heterostructures have successfully hosted quantum dot qubits, but the intrinsic near-degeneracy of the two lowest valley states poses an obstacle to high fidelity quantum computing.

Fast spin-valley-based quantum gates in Si with micromagnets

An electron spin qubit in silicon quantum dots holds promise for quantum information processing due to the scalability and long coherence. An essential ingredient to recent progress is the employment

References

SHOWING 1-10 OF 47 REFERENCES

Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting.

TLDR
It is demonstrated that valley separation can be accurately tuned via electrostatic gate control in a metal-oxide-semiconductor quantum dot, providing splittings spanning 0.3-0.8 meV, with a ratio in agreement with atomistic tight-binding predictions.

Valley dependent anisotropic spin splitting in silicon quantum dots

Spin qubits hosted in silicon (Si) quantum dots (QD) are attractive due to their exceptionally long coherence times and compatibility with the silicon transistor platform. To achieve electrical

Controllable valley splitting in silicon quantum devices

Silicon has many attractive properties for quantum computing, and the quantum-dot architecture is appealing because of its controllability and scalability. However, the multiple valleys in the

Control of valley dynamics in silicon quantum dots in the presence of an interface step

Recent experiments on silicon nanostructures have seen breakthroughs toward scalable, long-lived quantum information processing. The valley degree of freedom plays a fundamental role in these

Electron g -factor of valley states in realistic silicon quantum dots

We theoretically model the spin-orbit interaction in silicon quantum dot devices, relevant for quantum computation and spintronics. Our model is based on a modified effective mass approach which

Valley splitting in strained silicon quantum wells

A theory based on localized-orbital approaches is developed to describe the valley splitting observed in silicon quantum wells. The theory is appropriate in the limit of low electron density and

Spin-orbit coupling and operation of multivalley spin qubits

Spin qubits composed of either one or three electrons are realized in a quantum dot formed at a Si/SiO_2-interface in isotopically enriched silicon. Using pulsed electron spin resonance, we perform

Effects of interface steps on the valley-orbit coupling in a Si/SiGe quantum dot

Valley-orbit coupling is a key parameter for a silicon quantum dot in determining its suitability for applications in quantum information processing. In this paper we study the effect of interface

Spin relaxation in a Si quantum dot due to spin-valley mixing

We study the relaxation of an electron spin qubit in a Si quantum dot due to electrical noise. In particular, we clarify how the presence of conduction-band valleys influences spin relaxation. In

Magnetic field dependence of valley splitting in realistic Si∕SiGe quantum wells

The authors investigate the magnetic field dependence of the energy splitting between low-lying valley states for electrons in a Si∕SiGe quantum well tilted with respect to the crystallographic axis.