Cavity control over heavy-hole spin qubits in inversion-symmetric crystals

Mutter, Philipp M.; Burkard, Guido

doi:10.1103/physrevb.102.205412

Cited by 24 publications

(14 citation statements)

References 43 publications

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“…Furthermore, to introduce the transport formalism and investigate the effects of spin-polarized leads together with site-dependent g-tensors in a clear and disentangled fashion, the SOI has only been considered indirectly as one mechanism for spin relaxation so far. We now turn to a more complete description of the DQD system by explicitly including the SOI, which is ubiquitous in solid state systems and of great interest for qubit gate manipulation in spin based quantum information technology [44,45].…”

Section: B Arbitrary Polarizationsmentioning

confidence: 99%

Pauli spin blockade with site-dependent g-tensors and spin-polarized leads

Mutter,

Burkard

2021

Preprint

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Pauli spin blockade (PSB) in double quantum dots (DQDs) has matured into a prime technique for precise measurements of nanoscale system parameters. In this work we demonstrate that systems with site-dependent g-tensors and spin-polarized leads allow for a complete characterization of the g-tensors in the dots by magnetotransport experiments alone. Additionally, we show that special polarization configurations can enhance the often elusive magnetotransport signal, rendering the proposed technique robust against noise in the system, and inducing a giant magnetoresistance effect. Finally, we incorporate the effects of the spin-orbit interaction (SOI) and show that in this case the leakage current contains information about the degree of spin polarization in the leads.

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Section: B Arbitrary Polarizationsmentioning

confidence: 99%

Pauli spin blockade with site-dependent g-tensors and spin-polarized leads

Mutter,

Burkard

2021

Preprint

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“…Note that the physics of the hole spin qubit in a planar quantum dot may be totally different from that in a nanowire quantum dot. Take the recently extensively studied semiconductor Ge as an illustration [16][17][18][19][20][21], the lowest subband dispersion of the 2D hole gas in a Ge quantum well always has heavy hole character [22], and can be modeled by a parabolic curve with band minimum at the center of the k space [23]. While the low-energy subband dispersions of the 1D hole gas in a cylindrical Ge nanowire are quite different [24].…”

Section: Introductionmentioning

confidence: 99%

Searching strong `spin'-orbit coupled one-dimensional hole gas in strong magnetic fields

2021

Preprint

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We show that a strong 'spin'-orbit coupled one-dimensional (1D) hole gas is achievable via applying a strong magnetic field to the originally two-fold degenerate hole gas confined in a cylindrical Ge nanowire. Both strong longitudinal and strong transverse magnetic fields are feasible to achieve this goal. The induced low-energy subband dispersion of the hole gas can be written as E = 2 k 2 z /(2m * h ) + ασ z kz + g * h µBBσ x /2, a form that is exact the same as that of the electron gas in the conduction band. Also, the induced hole effective m * h (0.07 ∼ 0.08 me) and the 'spin'-orbit coupling α (0.4 ∼ 0.65 eV Å) have a small magnetic field dependence, while the effective g-factor g * h of the hole 'spin' only has a small magnetic field dependence in the large fields region.

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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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Cavity control over heavy-hole spin qubits in inversion-symmetric crystals

Cited by 24 publications

References 43 publications

Pauli spin blockade with site-dependent g-tensors and spin-polarized leads

Pauli spin blockade with site-dependent g-tensors and spin-polarized leads

Searching strong `spin'-orbit coupled one-dimensional hole gas in strong magnetic fields

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

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