Dynamical Mean Field Theory of Moir\'e Bilayer Transition Metal Dichalcogenides: Phase Diagram, Resistivity, and Quantum Criticality

TL;DR

This study uses dynamical mean field theory to explore the phase diagram, resistivity, and quantum criticality in moiré bilayer transition metal dichalcogenides, revealing complex electronic behaviors including strange metal phases and magnetic effects.

Contribution

It provides a detailed theoretical analysis of the moiré Hubbard model, connecting band structure tuning to various correlated electronic phases and transport phenomena.

Findings

Identification of Fermi liquid, strange metal, and quantum critical regions in the phase diagram.

Discovery of cube-root van Hove singularity leading to strange metal behavior.

Demonstration of magnetic order influence on resistivity.

Abstract

We present a comprehensive dynamical mean field study of the triangular lattice moir\'e Hubbard model, which is believed to represent the physics of moir\'e bilayer transition metal dichalcogenides. In these materials, important aspects of the band structure including the bandwidth and the order and location of van Hove singularities can be tuned by varying the interlayer potential. We present a magnetic and metal-insulator phase diagram and a detailed study of the dependence of the resistivity on temperature, band filling and interlayer potential. We find that transport displays Fermi liquid, strange metal and quantum critical behaviors in distinct regions of the phase diagram. Specifically, we find that the cube-root van Hove singularity ($\rho(\epsilon) \sim|\epsilon|^{-1 / 3}$) gives a strange metal behavior with a $T$-linear scattering rate and $\omega/T$ scaling. We show how magnetic order affects the resistivity. Our results elucidate the physics of the correlated states and the metal-insulator continuous transition recently observed in twisted homobilayer WSe$_2$ and heterobilayer MoTe$_2$/WSe$_2$ experiments.