Single-Electron Double Quantum Dots in Bilayer Graphene

Nano Letters, vol. 20, pp. 2005–2011

Abstract

We present transport measurements through an electrostatically defined bilayer graphene double quantum dot in the single-electron regime. With the help of a back gate, two split gates, and two finger gates, we are able to control the number of charge carriers on two gate-defined quantum dots independently between zero and five. The high tunability of the device meets requirements to make such a device a suitable building block for spin-qubits. In the single-electron regime, we determine interdot tunnel rates on the order of 2 GHz. Both, the interdot tunnel coupling as well as the capacitive interdot coupling increase with dot occupation, leading to the transition to a single quantum dot. Finite bias magneto-spectroscopy measurements allow to resolve the excited-state spectra of the first electrons in the double quantum dot and are in agreement with spin and valley conserving interdot tunneling processes.

Authors 7

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

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany

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

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany

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

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany

4. Kenji Watanabe

   National Institute for Materials Science

   Affiliation as printed

   National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan

5. Takashi Taniguchi

   National Institute for Materials Science

   Affiliation as printed

   National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan

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

   RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

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

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

   Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany