The electrical conductivity/resistivity of a two dimensional ( 2+1d ) system is a dimensionless quantity, and in many cases can be universal. Previous theories for metal-insulator transitions (MIT) of 2D electron systems (either driven by disorder or interaction) predicted a critical resistivity at the order of h/e^2. Recent experiment on the transition metal dichalcogenide (TMD) moiré heterostructures reported a continuous MIT driven by interaction, where the critical resistivity at low temperature is exceedingly larger than h/e^2, which calls for a new theory.

We propose a new theory for the exotic MIT which naturally leads to a large critical resistivity. We will also construct a metallic phase with strongly interacting electrons, which enjoys a perturbative description in terms of the dual vortex degree of freedom. We demonstrate that when the vortices form a Fermi liquid (a good metal), the electrical resistivity of the metallic phase at low temperature is far beyond the so-called Mott-Ioffe-Regal limit.

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