Freiburg 2019 – wissenschaftliches Programm
FM 40.3: Poster
Dienstag, 24. September 2019, 16:30–18:30, Tents
A spin qubit in 28Si/SiGe with 60 ppm 29Si — •Floyd Schauer1, Tom Struck2, Arne Hollmann2, Andreas Schmidbauer1, Carlo Peiffer1, Veit Langrock2, Helge Riemann3, Nikolay V. Abrosimov3, Lars R. Schreiber2, and Dominique Bougeard1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Regensburg, Germany — 2JARA-FIT Institute Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany — 3Leibniz-Institut für Kristallzüchtung, Berlin, Germany
28Si is a strong candidate for hosting spin qubits, promising long qubit coherence times in a technologically scalable environment. Electrostatically-defined quantum dots in 28Si/SiGe heterostructures have been proven to robustly allow the implementation of spin qubits, as long as their device-inherent valley splitting energy is sufficiently large to operate the qubit.
Here, we present the characterization of a gate-defined single spin qubit in a quantum dot layout with an integrated nanomagnet. The qubit is hosted in a molecular-beam epitaxy-grown 28Si/SiGe heterostructure presenting only 60 ppm residual 29Si. We determine the relevant single electron quantum dot energies, finding a robust valley splitting beyond 200 µeV and a well separated orbital energy beyond 1 meV. Below the valley splitting energy, we observe spin relaxation times T1>1 s which are independent of the externally applied magnetic field. Using electron dipole spin resonance, the manipulation of the qubit yields T2* ∼ 22 µs and long T2echo ∼ 127 µs.