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TT: Fachverband Tiefe Temperaturen

TT 43: Poster: Correlated Electrons II

TT 43.28: Poster

Wednesday, March 29, 2023, 15:00–18:00, P2/OG3

Magnetism of graphene beyond half filling using a mean-field approach — •Maxime Lucas, Andreas Honecker, and Guy Trambly de Laissardière — Laboratoire de Physique Théorique et Modélisation, CY Cergy Paris Université / CNRS, France

The discovery of correlations between electronic flat-band states due to a Moiré pattern in twisted bilayers of graphene [1] or other 2D materials has recently stimulated studies of their magnetic properties. It is shown experimentally and theoretically that the filling of the flat bands is an essential parameter for understanding their properties. However, the behavior of a simple graphene layer is still unclear. Indeed, its half-filled case is well known and it has been studied by various theoretical approaches (mean-field theories (MFT), Monte Carlo) [2], but beyond half filling its magnetic properties are still unknown. Here, we present a detailed study of graphene magnetism using a combination of the Hubbard model and MFT. We focus on non half-filling cases, taking into account non-collinear magnetic moments.
[1] Y. Cao et al., Nature 556, 43 (2018); Nature 556, 80 (2018)
[2] M. Raczkowski, R. Peters, T.T. Phùng, N. Takemori, F. F. Assaad, A. Honecker, J. Vahedi, Phys. Rev. B 101, 125103 (2020), and references therein