Twisted bilayer graphene (tBLG) near the magic angle is a unique platform where the combination of topology and strong correlations gives rise to exotic electronic phases. These phases are gate-tunable and related to the presence of flat electronic bands, isolated by single-particle band gaps. This enables gate-controlled charge confinement, essential for the operation of single-electron transistors (SETs), and allows to explore the interplay of confinement, electron interactions, band renormalisation and the moir\'e superlattice, potentially revealing key paradigms of strong correlations. Here, we present gate-defined SETs in near-magic-angle tBLG with well-tunable Coulomb blockade resonances. These SETs allow to study magnetic field-induced quantum oscillations in the density of states of the source-drain reservoirs, providing insight into gate-tunable Fermi surfaces of tBLG. Comparison with tight-binding calculations highlights the importance of displacement-field-induced band renormalisation crucial for future advanced gate-tunable quantum devices and circuits in tBLG including e.g. quantum dots and Josephson junction arrays.
@article{arxiv.2409.08154,
title = {Gate-defined single-electron transistors in twisted bilayer graphene},
author = {Alexander Rothstein and Ammon Fischer and Anthony Achtermann and Eike Icking and Katrin Hecker and Luca Banszerus and Martin Otto and Stefan Trellenkamp and Florian Lentz and Kenji Watanabe and Takashi Taniguchi and Bernd Beschoten and Robin J. Dolleman and Dante M. Kennes and Christoph Stampfer},
journal= {arXiv preprint arXiv:2409.08154},
year = {2025}
}