Excited States in Bilayer Graphene Quantum Dots.
- Kurzmann A Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Eich M Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Overweg H Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Mangold M Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Herman F Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Rickhaus P Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Pisoni R Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Lee Y Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Garreis R Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Tong C Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Watanabe K National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
- Taniguchi T National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
- Ensslin K Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- Ihn T Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland.
- 2019-08-07
Published in:
- Physical review letters. - 2019
English
We report ground- and excited-state transport through an electrostatically defined few-hole quantum dot in bilayer graphene in both parallel and perpendicular applied magnetic fields. A remarkably clear level scheme for the two-particle spectra is found by analyzing finite bias spectroscopy data within a two-particle model including spin and valley degrees of freedom. We identify the two-hole ground state to be a spin-triplet and valley-singlet state. This spin alignment can be seen as Hund's rule for a valley-degenerate system, which is fundamentally different from quantum dots in carbon nanotubes, where the two-particle ground state is a spin-singlet state. The spin-singlet excited states are found to be valley-triplet states by tilting the magnetic field with respect to the sample plane. We quantify the exchange energy to be 0.35 meV and measure a valley and spin g factor of 36 and 2, respectively.
- Language
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- English
- Open access status
- hybrid
- Identifiers
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- DOI 10.1103/PhysRevLett.123.026803
- PMID 31386494
- Persistent URL
- https://sonar.ch/global/documents/262458
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