Site-polarized Mott phases competing with a correlated metal in twisted WSe$_2$

TL;DR

This study uses dynamical mean-field theory to elucidate the complex interplay of electronic correlations, charge-transfer mechanisms, and phase competition in twisted WSe$_2$, explaining its rich phase diagram and transport phenomena.

Contribution

It provides a theoretical framework for understanding the correlated phases and metal-insulator transitions in twisted WSe$_2$ driven by interlayer potential and interactions.

Findings

Identification of a correlated metal competing with three site-polarized insulators.

Charge-transfer physics explains particle-hole asymmetry and phase transitions.

Proximity to a van Hove singularity influences the electronic phases.

Abstract

Twisted WSe$_2$ hosts superconductivity, metal-insulator phase transitions, and field-controllable Fermi-liquid to non-Fermi-liquid transport properties. In this work, we use dynamical mean-field theory to provide a coherent understanding of the electronic correlations shaping the twisted WSe$_2$ phase diagram. We find a correlated metal competing with three distinct site-polarized correlated insulators; the competition is controlled by interlayer potential difference and interaction strength. The insulators are characterized by a strong differentiation between orbitals with respect to carrier concentration and effective correlation strength. Upon doping, a strong particle-hole asymmetry emerges, resulting from a Zaanen-Sawatzky-Allen-type charge-transfer mechanism. The associated charge-transfer physics and proximity to a van Hove singularity in the correlated metal sandwiched between two site-polarized insulators naturally explains the interlayer potential-driven metal-to-insulator transition, particle-hole asymmetry in transport, and the coherence-incoherence crossover in $3.65^\circ$ twisted WSe$_2$.