Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow><mml:mi>MoSe</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mi>WSe</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> Heterobilayers

Charge separated interlayer excitons in transition metal dichalcogenide (TMDC) heterobilayers are being explored for moir\'e exciton lattices and condensates. The presence of permanent dipole moments the poorly screened Coulomb interaction make many body interactions particularly strong excitons. Here we reveal two distinct phase transitions MoSe2/WSe2 heterobilayer using time spatially resolved photoluminescence imaging: from trapped moir\'e-potential to modestly mobile gas as density increases ne/h ~ 1011 cm-2 highly charge electron/hole plasma > 1012 cm-2. latter is Mott confirmed photoconductivity measurements. These findings set fundamental limits achieving quantum states