Hole spin splitting in a Ge quantum dot with finite barriers

Fuente: arXiv
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Autores principales: Wang, Jiawei, Hu, Xuedong, Fotso, Herbert F
Formato: Preprint
Publicado: 2025
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author Wang, Jiawei
Hu, Xuedong
Fotso, Herbert F
author_facet Wang, Jiawei
Hu, Xuedong
Fotso, Herbert F
contents We study the low-energy spectrum of a single hole confined in a planar Ge quantum dot (QD) within the effective-mass formalism. The QD is sandwiched between two GeSi barriers of finite potential height grown along the [001] direction. To treat this finite barrier problem, we adopt an independent-band approach in dealing with boundary conditions. The effects of different system parameters are investigated, including the width of the out-of-plane confining well, the size of the dot, and silicon concentration in the confining layers. The more accurate finite-barrier model results in the non-negligible dependence of the anisotropic $g$-factor on the choice of boundary conditions and on the silicon concentration in the barrier. Furthermore, while the ideal model of a planar dot with a square-well heterostructure already has an intrinsic spin-orbit coupling, realistic effects arising from the experimental setup may give rise to additional contributions. We investigate the impact from the top-gate electric field and the residual tensile strain on the qubit states. The results indicate that these effects are important contributions to the total spin-orbit coupling which enables fast electric control.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11106
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hole spin splitting in a Ge quantum dot with finite barriers
Wang, Jiawei
Hu, Xuedong
Fotso, Herbert F
Mesoscale and Nanoscale Physics
Quantum Physics
We study the low-energy spectrum of a single hole confined in a planar Ge quantum dot (QD) within the effective-mass formalism. The QD is sandwiched between two GeSi barriers of finite potential height grown along the [001] direction. To treat this finite barrier problem, we adopt an independent-band approach in dealing with boundary conditions. The effects of different system parameters are investigated, including the width of the out-of-plane confining well, the size of the dot, and silicon concentration in the confining layers. The more accurate finite-barrier model results in the non-negligible dependence of the anisotropic $g$-factor on the choice of boundary conditions and on the silicon concentration in the barrier. Furthermore, while the ideal model of a planar dot with a square-well heterostructure already has an intrinsic spin-orbit coupling, realistic effects arising from the experimental setup may give rise to additional contributions. We investigate the impact from the top-gate electric field and the residual tensile strain on the qubit states. The results indicate that these effects are important contributions to the total spin-orbit coupling which enables fast electric control.
title Hole spin splitting in a Ge quantum dot with finite barriers
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2503.11106