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Signatures of heavy and light electrons in Magic Angle Twisted Bilayer Graphene
The topological character of the flat bands of twisted bilayer graphene (TBG) underlies the plethora of correlated phenomena found as a function of doping and temperature. Particularly, it determines the unconventional reorganization of the electronic spectrum, observed in the electronic cascades and detected with STM, inverse compressibility, transport and in the electronic bands recently measured with the Quantum Twisting Microscope (QTM). Our Dynamical Mean Field Theory + Hartree (DMFT+H) calculations on a heavy-fermion like model [1] with topologically fragile flat bands compare very well with STM, QTM, resistivity and inverse compressibility measurements [2,3]. At the heart of the strong electronic reorganization lies the formation of unconventional moments and heavy quasiparticles and a non-monotonic filling of the light electrons with increasing doping. After reviewing these properties and our predictions for the fingerprints in the optical spectrum and real space electronic properties that can be probed in future experiments, I will focus in our recent calculations at very low temperatures.
[1] M.J. Calderón and E. Bascones, PRB 102, 155149 (2020)
[2]A. Datta, M.J. Calderón, A. Camjayi and E. Bascones, Nat. Com 14, 5036 (2023)
[3] M.J. Calderón, A. Camjayi, A. Datta and E. Bascones, PRB-Letter 112, L041126 (2025)
[4] A. Camjayi, M.J. Calderón and E. Bascones, in preparation