Nature of the bandwidth-tuned Mott transition in moire semiconductors

In $\mathrm{MoTe_2}$/$\mathrm{WSe_2}$ heterobilayers (Li et al., Nature, 2021, arXiv:2103.09779) and twisted bilayer $\mathrm{WSe_2}$ (Ghiotto et al., Nature, 2021) at filling $\nu = 1$ (one hole per moire site of a triangular lattice), tuning the displacement field drives a metal-insulator transition at which the charge gap closes continuously and $\rho(T)$ shows quantum-critical scaling. Determine whether this is a continuous Mott transition from a Fermi liquid to a spin liquid with a spinon Fermi surface, a transition into a magnetically ordered insulator, or a disorder-broadened first-order transition. An answer specifies the insulating state, the critical exponents, and the behaviour of the effective mass and spin susceptibility at the critical point.

Thermodynamic measurement of electronic specific heat or spin susceptibility across the transition, together with optical or tunnelling measurement of the charge gap, showing whether a gapless spin sector survives in the insulator.