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arXiv · 2207.02175

Band Gap Opening in Bilayer Graphene-CrCl$_3$/CrBr$_3$/CrI$_3$ van der Waals Interfaces

Giulia Tenasini·David Soler-Delgado·Zhe Wang·Fengrui Yao·Dumitru Dumcenco·Enrico Giannini·Kenji Watanabe·Takashi Taniguchi·Christian Moulsdale·Aitor Garcia-Ruiz·Vladimir I. Fal'ko·Ignacio Gutiérrez-Lezama·Alberto F. Morpurgo
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Abstract

We report experimental investigations of transport through bilayer graphene (BLG)/chromium trihalide (CrX$_3$; X=Cl, Br, I) van der Waals interfaces. In all cases, a large charge transfer from BLG to CrX$_3$ takes place (reaching densities in excess of $10^{13}$ cm$^{-2}$), and generates an electric field perpendicular to the interface that opens a band gap in BLG. We determine the gap from the activation energy of the conductivity and find excellent agreement with the latest theory accounting for the contribution of the $\sigma$ bands to the BLG dielectric susceptibility. We further show that for BLG/CrCl$_3$ and BLG/CrBr$_3$ the band gap can be extracted from the gate voltage dependence of the low-temperature conductivity, and use this finding to refine the gap dependence on the magnetic field. Our results allow a quantitative comparison of the electronic properties of BLG with theoretical predictions and indicate that electrons occupying the CrX$_3$ conduction band are correlated.

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Giulia Tenasini, David Soler-Delgado, Zhe Wang, Fengrui Yao, Dumitru Dumcenco, Enrico Giannini, Kenji Watanabe, Takashi Taniguchi, Christian Moulsdale, Aitor Garcia-Ruiz, Vladimir I. Fal'ko, Ignacio Gutiérrez-Lezama, Alberto F. Morpurgo. 2022-07-05. Band Gap Opening in Bilayer Graphene-CrCl$_3$/CrBr$_3$/CrI$_3$ van der Waals Interfaces. https://doi.org/10.1021/acs.nanolett.2c02369

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