### Abstract

Electronic states and spin operation in coupled quantum dots are numerically studied, considering realistic shape of quantum dots and electron-electron interaction, (i) We evaluate the spin coupling J between two electron spins, as a function of magnetic field perpendicular to the quantum dots. We observe a transition from antiferromagnetic coupling (J > 0) to ferromagnetic coupling (J < 0) at magnetic field of a few Tesla. The spin coupling is hardly influenced by the size difference between the quantum dots if the energy levels are matched, (ii) We simulate SWAP gate operations by calculating the time development of two electron spins. We show that a sudden change of tunnel barrier may result in the gate errors. The spin exchange is incomplete in the presence of strong spin-orbit interaction in InGaAs.

Original language | English |
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Pages (from-to) | 554-556 |

Number of pages | 3 |

Journal | Physica Status Solidi (C) Current Topics in Solid State Physics |

Volume | 4 |

Issue number | 2 |

DOIs | |

Publication status | Published - 2007 |

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### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

**Numerical simulation of spin-qubit operation in coupled quantum dots.** / Goto, Daisuke; Eto, Mikio.

Research output: Contribution to journal › Article

*Physica Status Solidi (C) Current Topics in Solid State Physics*, vol. 4, no. 2, pp. 554-556. https://doi.org/10.1002/pssc.200673265

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TY - JOUR

T1 - Numerical simulation of spin-qubit operation in coupled quantum dots

AU - Goto, Daisuke

AU - Eto, Mikio

PY - 2007

Y1 - 2007

N2 - Electronic states and spin operation in coupled quantum dots are numerically studied, considering realistic shape of quantum dots and electron-electron interaction, (i) We evaluate the spin coupling J between two electron spins, as a function of magnetic field perpendicular to the quantum dots. We observe a transition from antiferromagnetic coupling (J > 0) to ferromagnetic coupling (J < 0) at magnetic field of a few Tesla. The spin coupling is hardly influenced by the size difference between the quantum dots if the energy levels are matched, (ii) We simulate SWAP gate operations by calculating the time development of two electron spins. We show that a sudden change of tunnel barrier may result in the gate errors. The spin exchange is incomplete in the presence of strong spin-orbit interaction in InGaAs.

AB - Electronic states and spin operation in coupled quantum dots are numerically studied, considering realistic shape of quantum dots and electron-electron interaction, (i) We evaluate the spin coupling J between two electron spins, as a function of magnetic field perpendicular to the quantum dots. We observe a transition from antiferromagnetic coupling (J > 0) to ferromagnetic coupling (J < 0) at magnetic field of a few Tesla. The spin coupling is hardly influenced by the size difference between the quantum dots if the energy levels are matched, (ii) We simulate SWAP gate operations by calculating the time development of two electron spins. We show that a sudden change of tunnel barrier may result in the gate errors. The spin exchange is incomplete in the presence of strong spin-orbit interaction in InGaAs.

UR - http://www.scopus.com/inward/record.url?scp=50049123693&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=50049123693&partnerID=8YFLogxK

U2 - 10.1002/pssc.200673265

DO - 10.1002/pssc.200673265

M3 - Article

AN - SCOPUS:50049123693

VL - 4

SP - 554

EP - 556

JO - Physica Status Solidi (C) Current Topics in Solid State Physics

JF - Physica Status Solidi (C) Current Topics in Solid State Physics

SN - 1862-6351

IS - 2

ER -