Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 40: Poster: Quantum Computation: Hardware Platforms

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 Bougeard11Institut 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.

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