First-principles theory of field-effect doping in transition-metal dichalcogenides: Structural properties, electronic structure, Hall coefficient, and electrical conductivity

Electrochemical doping in 2D transition-metal dichalcogenides (TDMs) aimed at creating field effect transistor (FET) conditions can allow one to explore interesting transport phenomena in reduced dimensionality. In this timely work, the authors thoroughly investigate from first principles how field-effect doping affects the structural properties, electronic structure, and Hall coefficient of mono- and few-layers TDMs. They show that (i) the models, typically, used to estimate the doping charge in FET devices cannot be applied to 2D TMDs and, (ii) given the multivalley nature of both the conduction and valence bands, small differences in the band structure can manifest in transport behavior that is very different from that predicted based on a single parabolic band.