Mapping g-factors and complex intervalley coupling in Si/SiGe by conveyor-mode shuttling

Fuente: arXiv
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Auteurs principaux: Volmer, Mats, Struck, Tom, Sala, Arnau, Tu, Jhih-Sian, Trellenkamp, Stefan, Esposti, Davide Degli, Scappucci, Giordano, Cywiński, Łukasz, Bluhm, Hendrik, Schreiber, Lars R.
Format: Preprint
Publié: 2026
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author Volmer, Mats
Struck, Tom
Sala, Arnau
Tu, Jhih-Sian
Trellenkamp, Stefan
Esposti, Davide Degli
Scappucci, Giordano
Cywiński, Łukasz
Bluhm, Hendrik
Schreiber, Lars R.
author_facet Volmer, Mats
Struck, Tom
Sala, Arnau
Tu, Jhih-Sian
Trellenkamp, Stefan
Esposti, Davide Degli
Scappucci, Giordano
Cywiński, Łukasz
Bluhm, Hendrik
Schreiber, Lars R.
contents As silicon spin qubit chips are increasing in qubit number and area, methods for the screening of qubit related material parameters become vital. Here we demonstrate the two-dimensional mapping of small variations of the electron g-factor of quantum dots formed in planar Si/SiGe quantum wells with precision better than $10^{-3}$ and with nanometer lateral resolution. We scan the electron g-factor across a 40 nm $\times$ 400 nm area and observe two g-factors per QD site which obey a striking symmetry and bimodal distribution across the area. These two g-factors relate to valley states of the electron in the quantum dot in agreement with a recent theoretical model. Using conveyor-belt shuttling of entangled electron spin pairs, complementary to the mapping of the local valley-splitting, we map the g-factor. We compare g-factor and valley splitting maps measured on the same device, and extract the complex intervalley coupling parameter along the shuttle trajectories applying a theoretical model of g-factor dependence on intervalley coupling. These maps will allow unprecedented insights into the spin-valley dynamics during qubit manipulation, readout and shuttling and serve as a benchmark for the engineering of Si/SiGe heterostructures for large-scale quantum chips.
format Preprint
id arxiv_https___arxiv_org_abs_2603_01844
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mapping g-factors and complex intervalley coupling in Si/SiGe by conveyor-mode shuttling
Volmer, Mats
Struck, Tom
Sala, Arnau
Tu, Jhih-Sian
Trellenkamp, Stefan
Esposti, Davide Degli
Scappucci, Giordano
Cywiński, Łukasz
Bluhm, Hendrik
Schreiber, Lars R.
Quantum Physics
Materials Science
As silicon spin qubit chips are increasing in qubit number and area, methods for the screening of qubit related material parameters become vital. Here we demonstrate the two-dimensional mapping of small variations of the electron g-factor of quantum dots formed in planar Si/SiGe quantum wells with precision better than $10^{-3}$ and with nanometer lateral resolution. We scan the electron g-factor across a 40 nm $\times$ 400 nm area and observe two g-factors per QD site which obey a striking symmetry and bimodal distribution across the area. These two g-factors relate to valley states of the electron in the quantum dot in agreement with a recent theoretical model. Using conveyor-belt shuttling of entangled electron spin pairs, complementary to the mapping of the local valley-splitting, we map the g-factor. We compare g-factor and valley splitting maps measured on the same device, and extract the complex intervalley coupling parameter along the shuttle trajectories applying a theoretical model of g-factor dependence on intervalley coupling. These maps will allow unprecedented insights into the spin-valley dynamics during qubit manipulation, readout and shuttling and serve as a benchmark for the engineering of Si/SiGe heterostructures for large-scale quantum chips.
title Mapping g-factors and complex intervalley coupling in Si/SiGe by conveyor-mode shuttling
topic Quantum Physics
Materials Science
url https://arxiv.org/abs/2603.01844