Print Email Facebook Twitter Atomic fluctuations lifting the energy degeneracy in Si/SiGe quantum dots Title Atomic fluctuations lifting the energy degeneracy in Si/SiGe quantum dots Author Paquelet Wuetz, B. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Stehouwer, L.E.A. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Zwerver, A.M.J. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Philips, S.G.J. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Xue, X. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Zheng, G. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Lodari, M. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Samkharadze, Nodar (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO) Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO) Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QN/Vandersypen Lab; Kavli institute of nanoscience Delft) Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft) Date 2022 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. To reference this document use: http://resolver.tudelft.nl/uuid:cf64ed54-f8f4-4280-82d6-438a2589324c DOI https://doi.org/10.1038/s41467-022-35458-0 ISSN 2041-1723 Source Nature Communications, 13 (1) Part of collection Institutional Repository Document type journal article Rights © 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 Files PDF s41467_022_35458_0.pdf 2.05 MB Close viewer /islandora/object/uuid:cf64ed54-f8f4-4280-82d6-438a2589324c/datastream/OBJ/view