Correlated Electron Effects in Chromium Trihalide Hetostructures with Graphene: A Tight-Binding Model Perspective

Igor Rozhansky; Vladimir Fal'ko

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arXiv · 2404.18858

Correlated Electron Effects in Chromium Trihalide Hetostructures with Graphene: A Tight-Binding Model Perspective

Igor Rozhansky·Vladimir Fal'ko

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Abstract

In this study, we present an effective tight-binding model for an accurate description of the lowest energy quadruplet of conduction band in a ferromagnetic CrX$_3$ monolayer, tuned to the complementary \textit{ab initio} density functional theory simulations. This model, based on a minimum number of chromium orbitals, captures a distinctively flat dispersion in those bands but requires taking into account hoppings beyond nearest neighbours, revealing ligand-mediated electron pathways connecting remote chromium sites. Doping of states in the lowest conduction band of CrX$_3$ requires charge transfer, which, according to recent studies, can occur in graphene(G)/CrX$_3$ heterostructures. Here, we use the detailed description of the lowest conduction band in CrI$_3$ to show that G/CrI$_3$/G and G/CrI$_3$ are type-II heterostructures where light holes in graphene would coexist with heavy electrons in the magnetic layer, where the latter can be characterised by Wigner parameter $r_s\sim 15-20$ (as estimated for hBN-encapsulated structures).

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Igor Rozhansky, Vladimir Fal'ko. 2024-04-29. Correlated Electron Effects in Chromium Trihalide Hetostructures with Graphene: A Tight-Binding Model Perspective. https://arxiv.org/abs/2404.18858

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