The role of α-RuCl₃ flat bands in G peak splitting in graphene/α-RuCl₃ heterostructures

Abstract α -RuCl 3 is known for its potential to realize a Kitaev quantum spin liquid by tuning the competing interactions, such as doping effects. Here, we investigated the doping effect of α -RuCl 3 /graphene heterostructures and observed a G peak splitting related to different spins, as revealed by Raman spectroscopy. The deliberate disruption of the heterostructure led to a transition from a double G peak to a single peak, underscoring the significance of interface quality. This finding was corroborated by density functional theory calculations. Additionally, we distinguished the contributions of doping and strain by employing Raman mapping, drawing comparisons to CrCl 3 /graphene heterostructures. These findings present a high-resolution technique for assessing the uniformity of similar heterostructure surfaces and investigating the behavior of distinct spins in Raman scattering influenced by magnetic proximity effects.