Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 12: Diamond and Related Dielectric Materials II
KFM 12.6: Vortrag
Mittwoch, 20. März 2024, 11:30–11:50, TC 010
Energy dissipation on magic angle twisted bilayer graphene — •Marcin Kisiel1, Alexina Ollier1, Urs Gysin1, Martino Poggio1, Xiaobo Lu2, Dmitri Efetov3, and Ernst Meyer1 — 1Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland — 2International Center for Quantum Materials, Collaborative Innovation Center of Quantum Matter, Peking University, 100871, Beijing, China — 3Department of Physics, Ludwig-Maximilians-University München, Geschwister- Scholl-Platz 1, 80539 München, Germany
While traditional Joule dissipation omnipresent in today's electronic devices is well understood, the energy loss of the strongly interacting electron systems remains largely unexplored. Twisted bilayer graphene (tBLG) is a host of interaction-driven correlated insulating phases, when the relative rotation is close to the magic angle (1.08deg). Here, we report on low temperature (5K) nanomechanical energy dissipation of tBLG measured by sharp tip of the pendulum atomic force microscope (pAFM). Ultrasensitive cantilever tip acting as an oscillating gate over the quantum device shows dissipation peaks attributed to different fractional filling of the flat energy bands. pAFM provides exquisite spatial resolution and thus allows to determine the twist angle distribution of tBLG. Application of magnetic fields provoked strong oscillations of the dissipation signal at 3/4 band filling, which we identified as familiar to Aharonov- Bohm oscillations arising from wavefunction interference present between domains of different doping.