Spin-valley coupling in single-electron bilayer graphene quantum dots

RePEc: Research Papers in Economics

Abstract

Abstract Understanding how the electron spin is coupled to orbital degrees of freedom, such as a valley degree of freedom in solid-state systems, is central to applications in spin-based electronics and quantum computation. Recent developments in the preparation of electrostatically-confined quantum dots in gapped bilayer graphene (BLG) enable to study the low-energy single-electron spectra in BLG quantum dots, which is crucial for potential spin and spin-valley qubit operations. Here, we present the observation of the spin-valley coupling in bilayer graphene quantum dots in the single-electron regime. By making use of highly-tunable double quantum dot devices we achieve an energy resolution allowing us to resolve the lifting of the fourfold spin and valley degeneracy by a Kane-Mele type spin-orbit coupling of ≈ 60 μeV. Furthermore, we find an upper limit of a potentially disorder-induced mixing of the $$K$$ K and $$K^{\prime}$$ K ′ states below 20 μeV.

Authors 10

1. Luca Banszerus corresponding Aachen JARA-FIT and 2nd Institute of Physics

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany

2. S. Möller Aachen JARA-FIT and 2nd Institute of Physics

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany

3. Corinne Steiner Aachen JARA-FIT and 2nd Institute of Physics

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany

4. Eike Icking Aachen JARA-FIT and 2nd Institute of Physics

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany

5. Stefan Trellenkamp

   Forschungszentrum Jülich

   Affiliation as printed

   Helmholtz Nano Facility, Forschungszentrum Jülich, Jülich, Germany

6. Florian Lentz

   Forschungszentrum Jülich

   Affiliation as printed

   Helmholtz Nano Facility, Forschungszentrum Jülich, Jülich, Germany

7. Kenji Watanabe

   National Institute for Materials Science

   Affiliation as printed

   Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan

8. Takashi Taniguchi

   National Institute for Materials Science

   Affiliation as printed

   International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan

9. Christian Volk

   Forschungszentrum Jülich

   Affiliation as printed

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich, Germany

10. Christoph Stampfer

    Forschungszentrum Jülich

    Affiliation as printed

    Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich, Germany