Metal-Insulator Transition with Charge Fractionalization*

It has been proposed that an extended version of the Hubbard model which potentially hosts rich possibilities of correlated physics may be well simulated by the transition metal dichalcogenide (TMD) moiré heterostructures. Motivated by recent reports of continuous metal-insulator transition (MIT) at half-filling, as well as correlated insulators at various fractional fillings in TMD moiré heterostructures, we propose a theory for the potentially continuous MIT with fractionalized electric charges. The charge fractionalization at the MIT will lead to experimental observable effects, such as a large universal resistivity jump and interaction-driven "bad metal" at the MIT, as well as special scaling of the quasi-particle weight with the tuning parameter. These predictions are different from the previously proposed theory for continuous MIT.