Electric dipole spin resonance in systems with a valley-dependent<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>g</mml:mi></mml:math>factor

Rančić, Marko J.; Burkard, Guido

doi:10.1103/physrevb.93.205433

Cited by 15 publications

(11 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We argue that these new interface SOC contributions are much stronger than possible bulk contributions. Compared to previous phenomenological approaches 7,8,10,24,26,51,52,[65][66][67][68][69] , the approach taken in this paper provides more rigorous ground for analyzing current and future experiments.…”

Section: Summary and Discussionmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

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 properly accounts for spin-valley boundary conditions, derived from the interface symmetry, and should have applicability for other heterostructures. We show how the valley-dependent interface-induced spin-orbit 2D (3D) interaction, under the presence of an electric field that is perpendicular to the interface, leads to a g-factor renormalization in the two lowest valley states of a silicon quantum dot. These g-factors can change with electric field in opposite direction when intervalley spin-flip tunneling is favored over intra-valley processes, explaining recent experimental results. We show that the quantum dot level structure makes only negligible higher order effects to the g-factor. We calculate the g-factor as a function of the magnetic field direction, which is sensitive to the interface symmetry. We identify spin-qubit dephasing sweet spots at certain directions of the magnetic field, where the g-factor renormalization is zeroed: these include perpendicular to the interface magnetic field, and also in-plane directions, the latter being defined by the interface-induced spin-orbit constants. The g-factor dependence on electric field opens the possibility for fast all-electric manipulation of an encoded, few electron spin-qubit, without the need of a nanomagnet or a nuclear spin-background. Our approach of an almost fully analytic theory allows for a deeper physical understanding of the importance of spin-orbit coupling to silicon spin qubits.

show abstract

Section: Summary and Discussionmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Applying strain raises four of the six valleys in energy such that there exists in silicon QDs an additional two-fold valley degeneracy which has the properties of a pseudo-spin [83]. This two-fold valley degeneracy can be lifted by interfaces in the 2DEG, however, the exact orientation and splitting of the valley depends on atomistic steps of the interface [321,322,323,324,325,326,327,328,329]. This makes the valley splitting very unpredictable, and it is unwanted in qubit implementations in silicon as it boosts up the already large Hilbert space of threespin qubits.…”

Section: Perspectivesmentioning

confidence: 99%

Three-electron spin qubits

Russ

Burkard

2017

J. Phys.: Condens. Matter

Self Cite

104

117

View full text Add to dashboard Cite

The goal of this article is to review the progress of three-electron spin qubits from their inception to the state of the art. We direct the main focus towards the exchange-only qubit (Bacon et al 2000 Phys. Rev. Lett. 85 1758-61, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each three-spin qubit we describe the qubit model, the envisioned physical realization, the implementations of single-qubit operations, as well as the read-out and initialization schemes. Two-qubit gates and decoherence properties are discussed for the RX qubit and the exchange-only qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the charge-stability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchange-only qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spin-charge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchange-only qubit and its modification, the RX qubit, whose single-qubit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of two-qubit operations are presented for the exchange-only qubits which can be divided into short-ranged and long-ranged interactions. Both of these interaction types are expected to be necessary in a large-scale quantum computer. The short-ranged interactions use the exchange coupling by placing qubits next to each other and applying exchange-pulses (DiVincenzo et al 2000 Nature 408 339, Fong and Wandzura 2011 Quantum Inf. Comput. 11 1003, Setiawan et al 2014 Phys. Rev. B 89 085314, Zeuch et al 2014 Phys. Rev. B 90 045306, Doherty and Wardrop 2013 Phys. Rev. Lett. 111 050503, Shim and Tahan 2016 Phys. Rev. B 93 121410), while the long-ranged interactions use the photons of a superconducting microwave cavity as a mediator in order to couple two qubits over long distances (Russ and Burkard 2015 Phys. Rev. B 92 205412, Srinivasa et al 2016 Phys. Rev. B 94 205421). The nature of the three-electron qubit states each having the same total spin and total spin in z-direction (same Zeeman energy) provides a natural protection against several sources of noise (DiVincenzo et al 2000 Nature 408 339, Taylor et al 2013 Phys. R...

show abstract

“…[ 48 ] Fortunately, recent experiment indicated that by using the silicon metal‐oxide‐semiconductor (Si‐MOS) platform the valley splitting can be as high as 0.8 meV. [ 49,50 ] In this way, the valley effect can also be safely neglected. According to the latest experiment, the relaxation time based on silicon platform has reached

T_{1} = 9 s

.…”

Section: Resultsmentioning

confidence: 99%

Universal Singlet‐Triplet Qubits Implemented Near the Transverse Sweet Spot

2021

View full text Add to dashboard Cite

The key to realizing fault‐tolerant quantum computation for singlet‐triplet (ST) qubits in semiconductor double quantum dot (DQD) is to operate both the single‐ and two‐qubit gates with high fidelity. The feasible way includes operating the qubit near the transverse sweet spot (TSS) to reduce the leading order of the noise, as well as adopting the proper pulse sequences which are immune to noise. The single‐qubit gates can be achieved by introducing an AC drive on the detuning near the TSS. The large dipole moment of the DQDs at the TSS has enabled strong coupling between the qubits and the cavity resonator, which leads to two‐qubit entangling gates. When operating in the proper region and applying modest pulse sequences, both single‐ and two‐qubit gates have fidelity higher than 99%. The results in this paper suggest that taking advantage of the appropriate pulse sequences near the TSS can be effective to obtain high‐fidelity ST qubits.

show abstract

Electric dipole spin resonance in systems with a valley-dependentgfactor

Cited by 15 publications

References 34 publications

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

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

Three-electron spin qubits

Universal Singlet‐Triplet Qubits Implemented Near the Transverse Sweet Spot

Contact Info

Product

Resources

About