Electrical control of the 
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 tensor of the first hole in a silicon MOS quantum dot

Liles, S. D.; Martins, Frederico Rodrigues; Miserev, Dmitry; Kiselev, A. A.; Thorvaldson, I. D.; Rendell, M. J.; Jin, Ik Kyeong; Hudson, Fay E.; Veldhorst, Menno; Itoh, Kohei M.; Sushkov, O. P.; Ladd, Thaddeus D.; Dzurak, A. S.; Hamilton, A. R.

doi:10.1103/physrevb.104.235303

Cited by 34 publications

(26 citation statements)

References 66 publications

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“…Note that numerous experiments have shown that g tensors of electrons confined in semiconductors can be tuned in situ by electric fields [31,[34][35][36][37]. Therefore, we regard the spinorbit-affected parameters, that is, the matrix elements of the g tensors, the exchange strength J, and the exchange rotation R, as tunable parameters.…”

Section: Setup and Background: Spin-orbit-coupled Two-spin Systemmentioning

confidence: 99%

Topological charge distributions of an interacting two-spin system

György

Varjas²,

Vrana³

et al. 2022

Phys. Rev. B

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Quantum systems are often described by parameter-dependent Hamiltonians. Points in parameter space where two levels are degenerate can carry a topological charge. Here we theoretically study an interacting two-spin system where the degeneracy points form a nodal loop or a nodal surface in the magnetic parameter space, similarly to such structures discovered in the band structure of topological semimetals. Key results of our work are that (1) we determine the topological charge distribution along these degeneracy geometries and (2) we show that these nonpointlike degeneracy patterns can be obtained not only by fine-tuning but they can be stabilized by spatial symmetries. Since simple spin systems such as the one studied here are ubiquitous in condensed-matter setups, we expect that our findings, and the physical consequences of these nontrivial degeneracy geometries, are testable in experiments with quantum dots, molecular magnets, and adatoms on metallic surfaces.

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Section: Setup and Background: Spin-orbit-coupled Two-spin Systemmentioning

confidence: 99%

Topological charge distributions of an interacting two-spin system

György

Varjas²,

Vrana³

et al. 2022

Phys. Rev. B

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“…Therefore, the shear strains εyz, εxz, and εxy drive rotations of the principal magnetic axes around x, y and z respectively. We can recover the experimental rotations assuming small εyz 0.035% and εxz 0.080%, which highlights the sensitivity of such quantum devices to residual strains 24,30,40 . Note that the possible rotation of the principal axes around z can not be resolved since the g-factors have not been measured in the xy plane (but may improve the overall agreement between theory and experiment, in particular for LSESG1); The detailed assessment of strains in such complex nanostructures is, however, difficult (in particular in the nitrides), and goes beyond the scope of this work.…”

Section: B Discussionmentioning

confidence: 55%

“…The fact that Z is not aligned along the channel implies a loss of the xy quasi-symmetry plane of gate G2 24 , and the existence of additional heavy-hole/light-hole mixing mechanisms. The most likely scenario is that QD2 is slightly displaced towards G3 (as suggested above), and experiences small process and cool-down strains 24,30 . In particular, shear strains control the phase of the heavy-hole/light-hole mixing matrix elements.…”

Section: B Discussionmentioning

confidence: 96%

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A single hole spin with enhanced coherence in natural silicon

Piot¹,

B.²,

Schmitt³

et al. 2022

Preprint

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Semiconductor spin qubits based on spin-orbit states are responsive to electric field excitation allowing for practical, fast and potentially scalable qubit control. Spinelectric susceptibility, however, renders these qubits generally vulnerable to electrical noise, which limits their coherence time. Here we report on a spin-orbit qubit consisting of a single hole electrostatically confined in a natural silicon metal-oxidesemiconductor device. By varying the magnetic field orientation, we reveal the existence of operation sweet spots where the impact of charge noise is minimized while preserving an efficient electric-dipole spin control. We correspondingly observe an extension of the Hahn-echo coherence time up to 88 µs, exceeding by an order of magnitude the best reported values for hole-spin qubits, and approaching the state-of-the-art for electron spin qubits with synthetic spin-orbit coupling in isotopically-purified silicon. This finding largely enhances the prospects of silicon-based hole spin qubits for scalable quantum information processing.

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“…All-electrical control of spin qubits via the spinorbit interaction can be used to achieve faster and more scalable control, however, the intrinsic spin-orbit coupling of electron spins are too weak to induce high-fidelity coherent rotations 5 . In contrast, hole spins are subject to stronger spin-orbit fields, enabling fast two-axis control of the qubit albeit with the drawback of sub-microsecond coherence times [6][7][8][9][10] .…”

mentioning

confidence: 99%

Dispersive readout of reconfigurable ambipolar quantum dots in a silicon-on-insulator nanowire

Duan,

Lehtinen,

Fogarty

et al. 2020

Preprint

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We report on ambipolar gate-defined quantum dots in silicon on insulator (SOI) nanowires fabricated using a customised complementary metal-oxide-semiconductor (CMOS) process. The ambipolarity was achieved by extending a gate over an intrinsic silicon channel to both highly doped n-type and p-type terminals. We utilise the ability to supply ambipolar carrier reservoirs to the silicon channel to demonstrate an ability to reconfigurably define, with the same electrodes, double quantum dots with either holes or electrons. We use gate-based reflectometry to sense the inter-dot charge transition(IDT) of both electron and hole double quantum dots, achieving a minimum integration time of 160(100) µs for electrons (holes). Our results present the opportunity to combine, in a single device, the long coherence times of electron spins with the electrically controllable holes spins in silicon.

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Electrical control of the g tensor of the first hole in a silicon MOS quantum dot

Cited by 34 publications

References 66 publications

Topological charge distributions of an interacting two-spin system

Topological charge distributions of an interacting two-spin system

A single hole spin with enhanced coherence in natural silicon

Dispersive readout of reconfigurable ambipolar quantum dots in a silicon-on-insulator nanowire

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