Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 24: Graphene and 2D Materials (joint session TT/HL)
HL 24.6: Talk
Wednesday, March 20, 2024, 10:45–11:00, H 3007
Atomistic approach to correlations in multilayer graphene — •Ammon Fischer1, Lennart Klebl2, Tim Wehling2, and Dante M. Kennes1,3 — 1Institute for Theory of Statistical Physics, RWTH Aachen University — 2I. Institute for Theoretical Physics, Universität Hamburg, Notkestraße 9-11, 22607 Hamburg, Germany — 3Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761 Hamburg, Germany
Multilayer graphene has recently attracted considerable attention due to the discovery of cascades of correlated states and superconductivity driven by displacement field tunable van-Hove singularities at low densities. While experimental efforts aim to stabilize correlated phases by proximity-induced spin-orbit coupling or by increasing the number of graphene layers in the stack, first-principle guided theoretical investigations are thwarted by the strong momentum-localization of the low-energy degrees of freedom around the valleys K,K'. Here, we discuss how correlated phenomena in few-layer graphene can be resolved by atomistic weak-coupling methods including the random-phase approximation and the functional renormalization group using ab-initio derived interaction profiles. We demonstrate that the gap between phenomenological continuum model studies and atomistic investigations can be bridged by a novel Wannierization procedure that permits to relax the strong momentum-localization of the low-energy Bloch states. This enables a well-defined downloading procedure of long-ranged Coulomb interactions to the valley-local flat bands of multilayer graphene systems subject to external displacement fields.
Keywords: bernal bilayer graphene; strongly-interacting electrons; wannier functions; ab-initio; weak-coupling