SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 35: Focus Session: Correlations in Moiré Quantum Matter I
TT 35.6: Talk
Wednesday, March 29, 2023, 17:45–18:00, HSZ 03
Transport and electron correlations in magic-angle twisted bilayer graphene: A dynamical mean field theory study — •Gautam Rai1, Lorenzo Crippa2, Giorgio Sangiovanni2, Roser Valenti3, and Tim Wehling1 — 1I. Institut für Theoretische Physik, Universität Hamburg, Hamburg, Germany — 2Institute for Theoretical Physics and Astrophysics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany — 3Institut für Theoretische Physik, Goethe-Universität Frankfurt am Main, Frankfurt am Main, Germany
Fully characterising the low-temperature phase diagram of magic-angle twisted bilayer graphene (MATBG) has proven to be one of the most compelling challenges in recent condensed matter physics. Correlation effects dominate due to the flatness of the low-energy bands. By varying doping and temperature, one can tune between superconductor, correlated-insulator, and strange metal phases. It has been difficult to apply standard strong-correlation computational techniques because of a topological obstruction, which precludes the existence of exponentially localized, symmetry-preserving Wannier functions for the flat bands. Recently, a heavy Fermion model has been proposed that successfully treats the hybrid localised-delocalised nature of MATBG [1]. We apply dynamical mean field theory (DMFT) to the heavy Fermion model to describe electron correlation effects in MATBG. In particular, we demonstrate how filling commensurability affects transport at low temperatures.
[1] Z. D. Song and B. A. Bernevig, PRL 129, 047601 (2022)