Anomalous electrical transport in orientationally controlled trinary hybrids of graphene and twisted bilayer molybdenum disulphide

Moire superlattices of two-dimensional (2D) materials oriented at low twist angles generate a large-scale interference pattern leading to strong interlayer coupling, which influences the band structure and introduces flatbands. Conventional electronic transport measurements have shown the effects of flatband physics, manifesting as correlated insulating states and emergent superconductivity. In this study, we probe the electronic states in a trinary hybrid of graphene and twisted bilayer (tbl) MoS2. Graphene acts as a sensing layer, which captures the electronic effects of the underlying substrate, and we observe certain anomalies in the electronic characteristics of graphene only in the presence of an underlying 58.5 degrees tbl MoS2, at low temperatures. Interestingly, graphene on tbl MoS2, with twist angle near 0 degrees or on natural bilayer MoS2, does not show any anomalies. Density functional theory calculations show several distinguishable peaks in the density of states at the conduction band edge of twisted MoS2 near 60 degrees. We speculate that the anomaly appears due to fermi level pinning of graphene owing to a large density of states in the flatbands of twisted bilayer MoS2. An analysis of the energetics in the graphene-MoS2 hybrid quantitatively agree with theoretical predictions.

Automated summary

This study investigates the electronic states of graphene and twisted bilayer MoS2, revealing certain anomalies in the electronic characteristics of graphene only in the presence of a MoS2 with a twist angle near 58.5 degrees, while no anomalies are observed in other cases.