Spin-orbit coupling by design in quantum state engineering of atomically defined quantum dots

• URL: http://arxiv.org/abs/2606.14487v1
• Date: Fri, 12 Jun 2026 14:23:04 GMT
• Title: Spin-orbit coupling by design in quantum state engineering of atomically defined quantum dots
• Abstract summary: We show control over the spin-orbit Hamiltonian in quantum dots by tailoring the confinement potential with atomic-scale precision.<n>We quantify the atomic level structure, both spatially resolving the orbital character of the electronic states and their magnetic-field evolution.<n>These effects can be described using a Hamiltonian that allows consistent treatment of the confinement-induced spin-orbit coupling.
• Score: 33.92987652786443
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Tuning spin-orbit coupling is essential in controlling both spin and charge in confined semiconductor nanostructures, yet it is rarely a truly controllable parameter. Here, we show control over the spin-orbit Hamiltonian in quantum dots and the resulting quantum states by tailoring the confinement potential with atomic-scale precision. Using scanning tunnelling microscopy and spectroscopy, we pattern individual Cs ions into designer quantum dot structures on the surface of indium antimonide, in which electrons from a two-dimensional electron gas are confined with chosen in-plane electric-field gradients. We then quantify the atomic level structure, both spatially resolving the orbital character of the electronic states and their magnetic-field evolution. We demonstrate that the level structure, including the induced zero-field splitting, can be tailored by the designed geometry of the local electric fields. These effects can be described using a Hamiltonian that allows consistent treatment of the confinement-induced spin-orbit coupling beyond the conventional Bychkov-Rashba description. This Hamiltonian is derived from a multiband k.p model and takes the energy dependence of the relevant physical parameters into account. Such precise control of spin-orbit coupling in semiconductor quantum dots is relevant to quantum and spintronic technologies.

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