A two-dimensional array of single-hole quantum dots

Riggelen, F. van; Hendrickx, Nico W.; Lawrie, William I. L.; Russ, Maximilian; Sammak, Amir; Scappucci, Giordano; Veldhorst, Menno

doi:10.1063/5.0037330

Cited by 34 publications

(19 citation statements)

References 44 publications

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“…Lately, heavy holes (HHs) confined in quantum dots (QDs) have gained ground in the race for a first scalable platform for quantum computation [1][2][3][4][5][6][7]. Different implementations such as HHs in single QDs [8] and flopping mode qubits [9] have been shown to allow for fast one and two qubit logic, externally controllable without the need for experimentally challenging components required in electronic systems such as oscillating magnetic fields or magnetic field gradients at the nano-scale [10][11][12][13][14].…”

Section: Introductionmentioning

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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Section: Introductionmentioning

confidence: 99%

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

Mutter,

Burkard

2021

Preprint

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“…As a result, the use of strongly correlated nanoscale structures in nanoelectronics and spintronics is being pursued, which requires a fundamental understanding of the interplay between transport properties and interactions. Furthermore, the degree of control and quality of fabrication in nanosystems gives rise to the possibility of engineered interactions, making quantum simulation possible (see, e.g., [11][12][13][14][15][16]). As there are typically only a single or a few active regions in nanoscale systemswhich is where interactions occur-they are natural quantum impurity problems.…”

Section: Introductionmentioning

confidence: 99%

Conductance of a Dissipative Quantum Dot: Nonequilibrium Crossover Near a Non-Fermi-Liquid Quantum Critical Point

Zhang,

Novais,

Baranger

2021

Preprint

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We find the nonlinear conductance of a dissipative resonant level in the nonequilibrium steady state near its quantum critical point. The system consists of a spin-polarized quantum dot connected to two resistive leads that provide ohmic dissipation. We focus on the crossover from the strong-coupling, non-Fermi-liquid regime to the weak-coupling, Fermi-liquid ground state, a crossover driven by the instability of the quantum critical point to hybridization asymmetry or detuning of the level in the dot. We show that the crossover properties are given by tunneling through an effective single barrier described by the boundary sine-Gordon model. The nonlinear conductance is then obtained from thermodynamic Bethe ansatz results in the literature, which were developed to treat tunneling in a Luttinger liquid. The current-voltage characteristics are thus found for any value of the resistance of the leads. For the special case of lead resistance equal to the quantum resistance, we find mappings onto, first, the two-channel Kondo model and, second, an effectively noninteracting model from which the nonlinear conductance is found analytically. A key feature of the general crossover function is that the nonequilibrium crossover driven by applied bias is different from the crossover driven by temperature-we find that the nonequilibrium crossover is substantially sharper. Finally, we compare to experimental results for both the bias and temperature crossovers: the agreement is excellent.

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“…These characteristics have facilitated the development of planar germanium quantum dots [42] and quantum dot arrays [43], long spin relaxation times [44], single-hole qubits [45], singlet-triplet qubits [46], twoqubit logic [36], and universal operation of a four-qubit germanium quantum processor [12]. The spin-orbit coupling in germanium avoids the need to implement components such as striplines and nanomagnets, promising scalability in two dimensions [12,47], crucial for the implementation of error correction codes [5].…”

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confidence: 99%