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Atomic fluctuations lifting the energy degeneracy in Si/SiGe quantum dots

Journal Article (2022)
Authors

B. Wuetz (TU Delft - BUS/Quantum Delft, Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre)

Lucas E.A. Stehouwer (TU Delft - QCD/Scappucci Lab, TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft)

A. M.J. Zwerver (Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/Vandersypen Lab)

S.G.J. Philips (TU Delft - QCD/Vandersypen Lab, Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre)

X. Xue (TU Delft - QCD/Vandersypen Lab, TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft)

Guoji Zheng (Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/Vandersypen Lab)

M. Lodari (TU Delft - QCD/Scappucci Lab, Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre)

N. Samkharadze (TU Delft - QuTech Advanced Research Centre, TNO, TU Delft - BUS/TNO STAFF)

Amir Sammak (TNO, TU Delft - BUS/TNO STAFF, TU Delft - QuTech Advanced Research Centre)

L. M. K. Vandersypen (Kavli institute of nanoscience Delft, TU Delft - QN/Vandersypen Lab, TU Delft - QuTech Advanced Research Centre)

Giordano Scappucci (Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/Scappucci Lab)

G.B. Cavadini (External organisation)

Research Institute
QuTech Advanced Research Centre
Copyright
© 2022 B. Paquelet Wuetz, L.E.A. Stehouwer, A.M.J. Zwerver, S.G.J. Philips, X. Xue, G. Zheng, M. Lodari, Nodar Samkharadze, A. Sammak, L.M.K. Vandersypen, G. Scappucci, More Authors
To reference this document use:
https://doi.org/10.1038/s41467-022-35458-0
More Info
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Publication Year
2022
Language
English
Copyright
© 2022 B. Paquelet Wuetz, L.E.A. Stehouwer, A.M.J. Zwerver, S.G.J. Philips, X. Xue, G. Zheng, M. Lodari, Nodar Samkharadze, A. Sammak, L.M.K. Vandersypen, G. Scappucci, More Authors
Research Institute
QuTech Advanced Research Centre
Issue number
1
Volume number
13
DOI:
https://doi.org/10.1038/s41467-022-35458-0
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Abstract

Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom in the formation of qubits. Despite attempts to enhance the valley energy splitting deterministically, by engineering a sharp interface, valley splitting fluctuations remain a serious problem for qubit uniformity, needed to scale up to large quantum processors. Here, we elucidate and statistically predict the valley splitting by the holistic integration of 3D atomic-level properties, theory and transport. We find that the concentration fluctuations of Si and Ge atoms within the 3D landscape of Si/SiGe interfaces can explain the observed large spread of valley splitting from measurements on many quantum dot devices. Against the prevailing belief, we propose to boost these random alloy composition fluctuations by incorporating Ge atoms in the Si quantum well to statistically enhance valley splitting.