Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 3: Quantum Dots and Wires: Transport
HL 3.4: Talk
Monday, March 18, 2024, 10:30–10:45, EW 202
Impact of competing energy scales on the shell-filling sequence in elliptic bilayer graphene quantum dots — •Lucca Valerius1, Samuel Möller1,2, Luca Banszerus1,2, Angelika Knothe3, Katrin Hecker1,2, Eike Icking1,2, Kenji Watanabe4, Takashi Taniguchi5, Christian Volk1,2, and Christoph Stampfer1,2 — 1JARA-FIT and 2nd Institute of Physics, RWTH Aachen, Germany — 2Peter Grünberg Institute, FZ Jülich, Germany — 3Institut für Theoretische Physik, Universität Regensburg, Germany — 4Research Center for Functional Materials, NIMS, Tsukuba, Japan — 5International Center for Materials Nanoarchitectonics, NIMS, Tsukuba, Japan
We investigate the shell-filling sequence of gate-defined elliptic bilayer graphene quantum dots (QDs) with low charge carrier occupation (N ≤ 12), using magnetotransport spectroscopy and numerical calculations. Considering short-range electron-electron interactions and wave-function-dependent valley g-factors, we deepen our understanding of the fourfold shell-filling sequence, emphasizing the need to include these factors. They introduce an additional energy splitting at half filling of each orbital state, and different energy shifts in out-of-plane magnetic fields. Our analysis of 31 bilayer graphene QDs shows that the valley g-factor and energy splitting increase as QD size decreases, aligning with theoretical predictions. The charging energy of these QDs does not consistently correlate with size, revealing complex electrostatics and offering insights for future BLG QD devices.
Keywords: Bilayer Graphene; Quantum Dots; Electron-electron interactions; Shell-filling; Valley magnetic moment