Phase Diagram of Electron–Hole Liquid in Monolayer Heterostructures Based on Transition Metal Dichalcogenides

The interest in monomolecular layers of transition metal dichalcogenides (TMDs), which has been shown in recent years, is due to their peculiar electronic and optical properties that are very attractive for designing functional elements of new-generation nanoelectronics. Experimental proofs of the formation of a high-temperature strongly bound electron–hole liquid (EHL) in TMD monolayers have been obtained recently. Strong coupling of charge carriers is associated with a considerable decrease in screening of the Coulomb interaction in monolayer heterostructures. In this study, the gas–liquid phase transition in the system of electrons and holes in quasi-two-dimensional TMD-based heterostructures is considered and critical parameters of such a transition are calculated. The insulator–metal transition is described and the phase diagram for such heterostructures is constructed.