Spin relaxation in a single-electron graphene quantum dot

Nature Communications, vol. 13, pp. 3637

Abstract

Abstract The relaxation time of a single-electron spin is an important parameter for solid-state spin qubits, as it directly limits the lifetime of the encoded information. Thanks to the low spin-orbit interaction and low hyperfine coupling, graphene and bilayer graphene (BLG) have long been considered promising platforms for spin qubits. Only recently, it has become possible to control single-electrons in BLG quantum dots (QDs) and to understand their spin-valley texture, while the relaxation dynamics have remained mostly unexplored. Here, we report spin relaxation times (T1) of single-electron states in BLG QDs. Using pulsed-gate spectroscopy, we extract relaxation times exceeding 200 μs at a magnetic field of 1.9 T. The T1 values show a strong dependence on the spin splitting, promising even longer T1 at lower magnetic fields, where our measurements are limited by the signal-to-noise ratio. The relaxation times are more than two orders of magnitude larger than those previously reported for carbon-based QDs, suggesting that graphene is a potentially promising host material for scalable spin qubits.

Authors 8

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

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen, Germany. luca.banszerus@rwth-aachen.de

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich, Germany. luca.banszerus@rwth-aachen.de

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

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

2. K. Hecker Aachen JARA-FIT and 2nd Institute of Physics

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

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

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

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

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

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

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

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

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

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

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

5. Kenji Watanabe

   National Institute for Materials Science

   Affiliation as printed

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

6. Takashi Taniguchi

   National Institute for Materials Science

   Affiliation as printed

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

7. Christian Volk Aachen JARA-FIT and 2nd Institute of Physics

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

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

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

8. Christoph Stampfer Aachen JARA-FIT and 2nd Institute of Physics

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

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

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