Sign switching of superexchange mediated by a few electrons in a nonuniform magnetic field

Guo Xuan Chan and Xin Wang
Phys. Rev. A 106, 022420 – Published 19 August 2022

Abstract

Long-range interaction between distant spins is an important building block for the realization of a large quantum-dot network in which couplings between pairs of spins can be selectively addressed. Recent experiments on the coherent oscillation of logical states between remote spins facilitated by intermediate electron states were the first step for large-scale quantum information processing. Reaching this ultimate goal requires extensive studies on the superexchange interaction in different quantum-dot spatial arrangements and electron configurations. Here, we consider a linear triple quantum dot with two antiparallel spins in the outer dots forming the logical states while varying numbers of electrons in the middle dot form a mediator, which facilitates the superexchange interaction. We show that the superexchange is enhanced when the number of mediating electrons increases. In addition, we show that forming a four-electron triplet in the mediator dot further enhances the superexchange strength. Our work can be a guide to scale up the quantum-dot array with controllable and dense connectivity.

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  • Received 6 April 2022
  • Accepted 8 August 2022

DOI:https://doi.org/10.1103/PhysRevA.106.022420

©2022 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & TechnologyCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Guo Xuan Chan and Xin Wang*

  • Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China and City University of Hong Kong Shenzhen Research Institute, Shenzhen, Guangdong 518057, China

  • *x.wang@cityu.edu.hk

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Issue

Vol. 106, Iss. 2 — August 2022

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