Band Gap Opening in Bilayer Graphene-CrCl₃/CrBr₃/CrI₃ van der Waals Interfaces

Abstract

We report the experimental investigation of transport through bilayer graphene (BLG)/chromium trihalide (CrX3; X=Cl, Br, I) van der Waals interfaces. In all cases, a large charge transfer from BLG to CrX3 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/CrCl3 and BLG/CrB3 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 magnetic field. Our results allow a quantitative comparison of the electronic properties of BLG with theoretical predictions and indicate the presence of correlations in electrons occupying CrX3 conduction band.

Gate-Tunable Renormalization of Spin-Correlated Flat-Band States and Bandgap in a 2D Magnetic Insulator

“…Upon reaching the edge of the CrBr 3 domain, the graphene became heavily p -doped, and the Dirac point position was determined to be E D = 0.32 eV, consistent with that of graphene beneath CrBr 3 (refer to SI, Figures S9–S10 and Note 1 for detailed descriptions of the assignment of E D ). p -doping is due to a significant charge transfer from graphene to CrBr 3 arising from the large work function difference between the two materials. , The charge transfer from graphene to other 2D magnetic materials have been reported by several groups. , Despite the CBM being positioned away from the Fermi level, the electronic hybridization between graphene and CrBr 3 could result in the formation of tail states, which facilitate the injection of charges from graphene into CrBr 3 . We noted that the E D of the graphene underneath CrBr 3 always lies above E F , slightly decreasing from 0.34 eV at V g = −40 to 0.30 eV at V g = −40 V. This means that the hole carrier density in the graphene substrate undergoes a monotonic decrease from 1.25 × 10 13 to 1.02 × 10 13 cm –2 within the accessible range of gate voltages.…”

“…p-doping is due to a significant charge transfer from graphene to CrBr 3 arising from the large work function difference between the two materials. 7,35 The charge transfer from graphene to other 2D magnetic materials have been reported by several groups. 36,37 Despite the CBM being positioned away from the Fermi level, the electronic hybridization between graphene and CrBr 3 could result in the formation of tail states, which facilitate the injection of charges from graphene into CrBr 3 .…”

Spin‐Selective Memtransistors with Magnetized Graphene

“…Additionally, several studies have delved into graphene properties such as the opening of band gaps in bilayer graphene /CrI 3 or the occurrence of anomalous Landau levels (LLs) in graphene on CrI 3 . [34,35] Despite these efforts, the intricate mechanisms underlying band hybridization in monolayer graphene/CrI 3 heterostructure are yet to be fully elucidated.…”

Giant Third-Order Nonlinear Hall Effect in Misfit Layer Compound (SnS)1.17(NbS2)3

“…However, current studies are confined to individual materials, where THE presents due to their inherent electronic and structural properties, leaving behind investigations on interfacial structural engineering in heterostructures. Interface interaction in van der Waals materials offers an effective approach for modifying band arrangements. − Taking advantage of the interface interaction, misfit layer compounds intensified the effect by the alternate stacking of transition metal dichalcogenides (TMD) and rock salt chalcogenides. , Various novel phenomena were explored within this category, including Ising superconductivity and nonreciprocal transport. − Both experimental and theoretical works highlight the potency of manipulating the spatial and electronic structures in these misfit layer compounds.…”