# Simulation of micro-magnet stray-field dynamics for spin qubit manipulation

## Abstract

High-fidelity control and unprecedented long dephasing times in silicon-based single spin qubits have recently confirmed the prospects of solid-state quantum computation. We investigate the feasibility of using a micro-magnet stray field for all-electrical, addressable spin qubit control in a Si/SiGe double quantum dot. For a micro-magnet geometry optimized for high Rabi-frequency, addressability, and robustness to fabrication misalignment as previously demonstrated by Yoneda et al. [Phys. Rev. Lett. 113, 267601 (2014)], we simulate the qubit decoherence due to magnetic stray-field fluctuations, which may dominate in nuclear spin-free systems, e.g., quantum dots in Si/SiGe, Si-MOS structures and (bilayer) graphene. With calculated Rabi-frequencies of 15 MHz, a qubit addressability error below 10{sup −3} is achievable. Magnetic fluctuations from a micro-magnet limits the spin relaxation time to T{sub 1} ≳ 3 s, while pure spin dephasing is negligible. Our results show that micro-magnets are a promising tool for spin qubit computation in nuclear spin-free systems.

- Authors:

- Quantum Technology Group, JARA-Institute for Quantum Information, RWTH Aachen University, 52056 Aachen (Germany)

- Publication Date:

- OSTI Identifier:
- 22410209

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Applied Physics

- Additional Journal Information:
- Journal Volume: 117; Journal Issue: 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 77 NANOSCIENCE AND NANOTECHNOLOGY; CALCULATION METHODS; FLUCTUATIONS; GERMANIUM SILICIDES; GRAPHENE; LAYERS; MAGNETS; MHZ RANGE; QUANTUM COMPUTERS; QUANTUM DOTS; QUBITS; RELAXATION TIME; SILICON; SILICON OXIDES; SOLIDS; SPIN

### Citation Formats

```
Neumann, R., and Schreiber, L. R., E-mail: lars.schreiber@physik.rwth-aachen.de.
```*Simulation of micro-magnet stray-field dynamics for spin qubit manipulation*. United States: N. p., 2015.
Web. doi:10.1063/1.4921291.

```
Neumann, R., & Schreiber, L. R., E-mail: lars.schreiber@physik.rwth-aachen.de.
```*Simulation of micro-magnet stray-field dynamics for spin qubit manipulation*. United States. doi:10.1063/1.4921291.

```
Neumann, R., and Schreiber, L. R., E-mail: lars.schreiber@physik.rwth-aachen.de. Thu .
"Simulation of micro-magnet stray-field dynamics for spin qubit manipulation". United States. doi:10.1063/1.4921291.
```

```
@article{osti_22410209,
```

title = {Simulation of micro-magnet stray-field dynamics for spin qubit manipulation},

author = {Neumann, R. and Schreiber, L. R., E-mail: lars.schreiber@physik.rwth-aachen.de},

abstractNote = {High-fidelity control and unprecedented long dephasing times in silicon-based single spin qubits have recently confirmed the prospects of solid-state quantum computation. We investigate the feasibility of using a micro-magnet stray field for all-electrical, addressable spin qubit control in a Si/SiGe double quantum dot. For a micro-magnet geometry optimized for high Rabi-frequency, addressability, and robustness to fabrication misalignment as previously demonstrated by Yoneda et al. [Phys. Rev. Lett. 113, 267601 (2014)], we simulate the qubit decoherence due to magnetic stray-field fluctuations, which may dominate in nuclear spin-free systems, e.g., quantum dots in Si/SiGe, Si-MOS structures and (bilayer) graphene. With calculated Rabi-frequencies of 15 MHz, a qubit addressability error below 10{sup −3} is achievable. Magnetic fluctuations from a micro-magnet limits the spin relaxation time to T{sub 1} ≳ 3 s, while pure spin dephasing is negligible. Our results show that micro-magnets are a promising tool for spin qubit computation in nuclear spin-free systems.},

doi = {10.1063/1.4921291},

journal = {Journal of Applied Physics},

issn = {0021-8979},

number = 19,

volume = 117,

place = {United States},

year = {2015},

month = {5}

}