Radio-frequency charge detection on graphene electron-hole double quantum dots
Authors:
Katrin Hecker,
Samuel Möller,
Hubert Dulisch,
Şiyar Duman,
Leon Stecher,
Lucca Valerius,
Tobias Deußen,
Saketh Ravuri,
Kenji Watanabe,
Takashi Taniguchi,
Florian Libisch,
Christian Volk,
Christoph Stampfer
Abstract:
High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a capacitively coupled quantum point contact (QPC). The device design suppresses screening effects and enables sensitive QPC-based charge readout. The QPC is arranged t…
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High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a capacitively coupled quantum point contact (QPC). The device design suppresses screening effects and enables sensitive QPC-based charge readout. The QPC is arranged to maximize the readout contrast between two neighboring, coupled electron and hole QDs. We apply the readout scheme to a single-particle electron-hole double QD and demonstrate time-resolved detection of charge states as well as magnetic field dependent tunneling rates. This promises a high-fidelity readout scheme for individual spin and valley states, which is important for the operation of spin, valley or spin-valley qubits in bilayer graphene.
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Submitted 1 December, 2025; v1 submitted 15 September, 2025;
originally announced September 2025.
Liquid-phase exfoliated indium-selenide flakes and their application in hydrogen evolution reaction
Authors:
Elisa Petroni,
Emanuele Lago,
Sebastiano Bellani,
Danil W. Boukhvalov,
Antonio Politano,
Bekir Gurbulak,
Songul Duman,
Mirko Prato,
Silvia Gentiluomo,
Reinier Oropesa-Nunez,
Jaya-Kumar Panda,
Peter S. Toth,
Antonio Esau Del Rio Castillo,
Vittorio Pellegrini,
Francesco Bonaccorso
Abstract:
Single- and few-layered InSe flakes are produced by the liquid-phase exfoliation of beta-InSe single crystals in 2-propanol, obtaining stable dispersions with a concentration as high as 0.11 g/L. Ultracentrifugation is used to tune the morphology, i.e., the lateral size and thickness of the as-produced InSe flakes. We demonstrate that the obtained InSe flakes have maximum lateral sizes ranging fro…
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Single- and few-layered InSe flakes are produced by the liquid-phase exfoliation of beta-InSe single crystals in 2-propanol, obtaining stable dispersions with a concentration as high as 0.11 g/L. Ultracentrifugation is used to tune the morphology, i.e., the lateral size and thickness of the as-produced InSe flakes. We demonstrate that the obtained InSe flakes have maximum lateral sizes ranging from 30 nm to a few um, and thicknesses ranging from 1 to 20 nm, with a max population centred at ~ 5 nm, corresponding to 4 Se-In-In-Se quaternary layers. We also show that no formation of further InSe-based compounds (such as In2Se3) or oxides occurs during the exfoliation process. The potential of these exfoliated-InSe few-layer flakes as a catalyst for hydrogen evolution reaction (HER) is tested in hybrid single-walled carbon nanotubes/InSe heterostructures. We highlight the dependence of the InSe flakes morphologies, i.e., surface area and thickness, on the HER performances achieving best efficiencies with small flakes offering predominant edge effects. Our theoretical model unveils the origin of the catalytic efficiency of InSe flakes, and correlates the catalytic activity to the Se vacancies at the edge of the flakes.
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Submitted 21 March, 2019;
originally announced March 2019.