Doping a Wigner-Mott insulator: Exotic charge orders in transition-metal dichalcogenide moir\'e heterobilayers

TL;DR

This paper explores the complex electronic phases in transition-metal dichalcogenide moiré heterobilayers, revealing new charge orders and a novel 'electron slush' state driven by electron interactions in flat bands.

Contribution

It introduces the concept of an 'electron slush' state and analyzes nontrivial phases away from commensurate fillings in moiré heterobilayers.

Findings

Identification of doped Wigner-Mott charge transfer insulators

Discovery of a conducting 'electron slush' state with frozen charge order

Proposal of inhomogeneous local density of states as a key signature

Abstract

The moir\'e pattern induced by lattice mismatch in transition-metal dichalcogenide heterobilayers causes the formation of flat bands, where interactions dominate the kinetic energy. At fractional fillings of the flat valence band, the long-range electron interactions then induce Wigner-Mott crystals. In this Letter we investigate the nontrivial electronic phases appearing away from commensurate fillings. Here, competing phases arise that are either characterized as doped Wigner-Mott charge transfer insulators or alternatively, a novel state with frozen charge order yet is conducting: the 'electron slush'. We propose that an extremely spatially inhomogeneous local density of states can serve as a key signature of the electron slush.