Hole spin splitting in a Ge quantum dot with finite barriers

• URL: http://arxiv.org/abs/2503.11106v1
• Date: Fri, 14 Mar 2025 05:59:04 GMT
• Title: Hole spin splitting in a Ge quantum dot with finite barriers
• Authors: Jiawei Wang, Xuedong Hu, Herbert F Fotso,
• Abstract summary: We study the low-energy spectrum of a single hole confined in a planar Ge quantum dot (QD)<n>The QD is sandwiched between two GeSi barriers of finite potential height grown along the [001] direction.<n>We investigate the impact from the top-gate electric field and the residual tensile strain on the qubit states.
• Score: 2.4054544518909076
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: 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.

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