Electronic compressibility of MATBG
ABSTRACT
In this work we develop a simple model able to capture the exotic phenomenology shown in recent transport measures of Magic-Angle Twisted Bilayer Graphene (MATBG) when the system is being doped. As MATBG exhibits narrow bands in the near zero energy region of the electronic structure, we take into account an efective electronic interaction between carriers of different flavour (valley and spin) in these flat bands. As a result of this interaction the charge neutrality point (CNP) of each flavour is shifted differently which lead to the caracteristic flavour symmetry broken electronic state and the cascade of phase transitions observed experimentally.
PRESENTER
Alejandro Jimeno Pozo
IMDEA Nanociencia
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Hi Alejandro, how is your approach related to a self-consistent Hartree approximation?
Hi Oskar, thank you for your reply.
The approach I have used here is not a self-consistent Hartree approximation. It is based on the simple model (I mean density of states, populations and kinetic energy defined as shown in ‘Model’ box in the poster) for mean-field grand potential PHI_MF, but I include a new parameter (that was not included in [4], but allow us to see similar results with no need of a Hartree-Fock method), i.e. DELTA_alpha, that corresponds to an effective shiftness of the CNP of each flavour, and then minimize the grand-potential with respect to this new variable.
Ping me at alejandro.jimeno@imdea.org if you have any insight about this want to discuss something else on this issue. Thanks!