SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 29: Materials and devices for quantum technology I
HL 29.1: Talk
Wednesday, March 29, 2023, 15:00–15:15, POT 151
Mapping of the local valley splitting in a Si/SiGe qubit shuttle device — •Bingjie Chen1, Mats Volmer1, Tom Struck1, Ran Xue1, Inga Seidler1, Joachim Knoch2 und Lars R. Schreiber1 — 1JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Germany — 2Institut für Halbleitertechnik, RWTH Aachen University, Germany
Qubits based on the electron spin in gate-defined 28Si/SiGe quantum dots (QD) are one of the major candidates for the quantum information processing. Due to weak spin-orbit coupling and low hyperfine interaction, their fidelity threshold for quantum error correction is reached. However, valley-state excitations [1-3] have implications for spin dephasing during qubit shuttling [4]. In our experiment, we map the valley splitting energy (EVS) originating from the quantum well confinement at different locations of a qubit shuttle device [5]. We measure their orbital splitting and spin-polarization as a function of various electron fillings and magnetic fields [6]. We fit the local singlet-triplet splitting energy as a lower boundary of the relevant EVS, which is distributed in a range of 11...73 µeV. The correlation length is approximatly the QD size and small dependence on the electric field perpendicular to the quantum well is found. [1]Dodson, J.P. ea., arXiv:2103.14702.[2]McJunkin, T. ea., Phys. Rev. B 104, 085406.[3]Hollman, A. ea., Phys. Rev. Applied 13, 034068.[4]Langrock, V. ea., arXiv: 2202.11793.[5]Seidler, I. ea., npj Quantum Inf. 8, 100.[6]Friessen. M. ea., Phys. Rev. B 75, 115318. This work has been funded by the German Research Foundation (DFG) within the project KN 545/28-1.