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

Abstract

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) MoS 2 . 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 tbl MoS 2 , at low temperatures. Interestingly, graphene on tbl MoS 2 , with twist angle near 0 or on natural bilayer MoS 2 , 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 MoS 2 near 60 . 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 MoS 2 . An analysis of the energetics in the graphene-MoS 2 hybrid quantitatively agree with theoretical predictions.

Emergent Inhomogeneity and Nonlocality in a Graphene Field-Effect Transistor on a Near-Parallel Moiré Superlattice of Transition Metal Dichalcogenides

“…Here we investigate electrical transport in vdW heterostructures with graphene placed over tTMDC bilayers, where the individual layers are twisted at near-parallel orientation. Graphene–TMDC heterostructures have been extensively used to probe the electronic, , optoelectronic, and spintronic properties . In the present work, graphene is used as the channel layer placed directly on a near-parallel (twist angle θ = 2.1°) WSe 2 bilayer, thus making the latter a part of the (bottom) gate stack.…”