High-resolution Landau level spectroscopy of magic-angle twisted bilayer graphene
ORAL
Abstract
Spectroscopy with scanning tunneling microscopy (STM) in a high magnetic field can be used to probe the quantization of the density of states into Landau levels (LL), which provides important information on electronic properties such as the relevance of broken symmetries and the presence or absence of Dirac cones. We apply this technique to study gated magic-angle twisted bilayer graphene (MATBG) devices, for which recent magnetotransport studies have reported transitions in the LL fan diagrams as a function of the filling of electrons in MATBG’s flat bands [1-3]. These reported changes correlate with the appearance of various correlated insulating, magnetic, and superconducting phases. Our STM measurements are carried out in a dilution-fridge system allowing us to resolve the energy of the LL with high resolution and to probe MATBG devices as a function of filling of its flat band. We will describe these measurements, their connection to the magnetotransport studies, and their interpretations in terms of microscopic properties of MATBG as a function of electron density.
[1] Y. Cao et al. Nature 556, 43 (2018)
[2] M. Yankowitz et al. Science 363, 1059 (2019)
[3] X. Lu et al. arXiv:1903.06513
[1] Y. Cao et al. Nature 556, 43 (2018)
[2] M. Yankowitz et al. Science 363, 1059 (2019)
[3] X. Lu et al. arXiv:1903.06513
*This work is supported by the Moore Foundation and the DOE.
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Presenters
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Dillon Wong
- Joseph Henry Laboratories & Department of Physics, Princeton University