  Strong correlations between electrons and holes can drive the existence of an
electron-hole liquid (EHL) state, typically at high carrier densities and low
temperatures. The recent emergence of quasi-2D monolayer transition metal
dichalcogenides (TMDCs) provide ideal systems to explore the EHL state since
ineffective screening of the out of plane field lines in these quasi-2D systems
allows for stronger charge carrier correlations in contrast to conventional 3D
bulk semiconductors and enabling the existence of the EHL at high temperatures.
Here we construct the phase diagram for the photo-induced first-order phase
transition from a plasma of electron-hole pairs to a correlated EHL state in
suspended monolayer MoS2. We show that quasi-2D nature of monolayer TMDCs and
the ineffective screening of the out of plane field lines allow for this phase
transition to occur at and above room temperature, thereby opening avenues for
studying many-body phenomena without the constraint of cryogenics.
