Anisotropic <i>g</i>-Factor and Spin–Orbit Field in a Germanium Hut Wire Double Quantum Dot

Zhang, Ting; Li, He; Gao, Fei; Xu, Gang; Wang, Ke; Zhang, Xin; Cao, Gang; Wang, Ting; Zhang, Jianjun; Hu, Xuedong; Li, Haiou; Guo, Guo-Ping

doi:10.1021/acs.nanolett.1c00263

Cited by 23 publications

(19 citation statements)

References 80 publications

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“…1f , we use g -factors of 7 and 3.95 for the two dots. With such different g -factors 30 , 31 , 46 , the two-spin states in the (1,1) regime should be spin product states for any magnetic field above 0.1 T. In the following, we focus on two of these resonances, denoted as mode A and mode B in Fig. 1c .…”

Section: Resultsmentioning

confidence: 99%

“…The particularly large Rabi frequency in mode A may have been enhanced by the low-energy excited state included in our model (Supplementary Note 2 and 10 ), a fact that has previously been exploited to enhance spin-electric-field coupling 50 , 51 . To obtain a deeper understanding of such strong spin–orbit coupling, anisotropy spectroscopy would be a viable method to reveal the underlying mechanisms 46 , 52 . Even though the Rabi frequency of 540 MHz is limited by unwanted PAT and heating effects at high microwave power, we believe it is still not the upper bound for the Rabi frequency of a GHW hole spin qubit.…”

Section: Discussionmentioning

confidence: 99%

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Ultrafast coherent control of a hole spin qubit in a germanium quantum dot

Wang

Gao

et al. 2022

Nat Commun

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Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo’s criteria for a scalable quantum information processor.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Ultrafast coherent control of a hole spin qubit in a germanium quantum dot

Wang

Gao

et al. 2022

Nat Commun

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“…Further research by Bychkov and Rashba demonstrated that the Rashba effect also occurs in quasi-2D systems . Over the past few decades, the Rashba effect and Dresselhaus effect have been observed in various systems, such as 2D semiconductors, heterostructures, metal surfaces, 3D bulk materials, and quantum wells. ,,− …”

Section: Origin Of Rashba and Dresselhaus Effects In 2d Electron Gasmentioning

confidence: 99%

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

Chen

et al. 2021

J. Phys. Chem. Lett.

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This theoretical Perspective reviews spin−orbit coupling (SOC), including the Rashba effect and Dresselhaus effect, in two-dimensional (2D) semiconductors. We first introduce the origin of the Rashba effect and Dresselhaus effect using the Hamiltonian models; we then summarize 2D Rashba semiconductors predicted by first-principles density functional theory (DFT) calculations, including AB binary monolayers, Janus monolayers, 2D perovskites, and so on. We also review various manipulating techniques of the Rashba effect on 2D semiconductors, such as external electric field, strain engineering, charge doping, interlayer interactions, proximity effect of substrates, and external magnetic field. We then briefly summarize the applications of SOC, including the generation, detection, and manipulation of spin currents in spin Hall effect transistors and spin field effect transistors. Finally, we conclude this Perspective and propose three promising research fields of SOC in low-dimensional semiconductors, including the nonlinear SOC Hamiltonian model, 2D ferroelectric SOC semiconductors, and 1D Rashba model and semiconductors. This theoretical Perspective enriches the fundamental understanding of SOC in 2D semiconductors and will help in the design of new types of spintronic devices in future experiments.

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“…Finally, we point out another application of our results, which is the reverse argumentation of before. By studying the avoided crossing between the ground state singlet and one of the triplet states, one may obtain information about the SOI in the system if the g tensors are known, e.g., from magneto-transport measurements [45,46]. The experimental parameters used when the crossing vanishes, e.g.…”

Section: B Transverse Couplingmentioning

confidence: 99%

All-electrical control of hole singlet-triplet spin qubits at low leakage points

Mutter,

Burkard

2021

Preprint

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We study the effect of the spin-orbit interaction on heavy holes confined in a double quantum dot in the presence of a magnetic field of arbitrary direction. Rich physics arise as the two hole states of different spin are not only coupled by the spin-orbit interaction but additionally by the effect of site-dependent anisotropic g tensors. It is demonstrated that these effects may counteract in such a way as to cancel the coupling at certain detunings and tilting angles of the magnetic field. This feature may be used in singlet-triplet qubits to avoid leakage errors and implement an electrical spinorbit switch, suggesting the possibility of task-tailored two-axes control. Additionally, we investigate systems with a strong spin-orbit interaction at weak magnetic fields. By exact diagonalization of the dominant Hamiltonian we find that the magnetic field may be chosen such that the qubit ground state is mixed only within the logical subspace for realistic system parameters, hence reducing leakage errors and providing reliable control over the qubit.

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Anisotropic g-Factor and Spin–Orbit Field in a Germanium Hut Wire Double Quantum Dot

Cited by 23 publications

References 80 publications

Ultrafast coherent control of a hole spin qubit in a germanium quantum dot

Ultrafast coherent control of a hole spin qubit in a germanium quantum dot

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

All-electrical control of hole singlet-triplet spin qubits at low leakage points

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