Emergence of Chern metal in a moir\'e Kondo lattice

TL;DR

This paper reports the experimental discovery of a Chern metal state in a moiré Kondo lattice, revealing a new quantum phase with chiral edge states near Kondo breakdown, advancing understanding of topological correlated materials.

Contribution

It demonstrates the realization of a Chern metal in a frustrated moiré Kondo lattice, showing its properties and separating it from other known phases, which was not achieved before.

Findings

Observation of a nearly quantized Hall resistance with finite longitudinal resistance.

Detection of chiral edge states via nonlocal transport measurements.

Identification of a magnetization plateau indicating a Chern metal phase.

Abstract

A Chern metal is a two-dimensional metallic state of matter carrying chiral edge states. It can emerge as a doped Chern insulator, but theoretical studies have also predicted its emergence near a Kondo breakdown separating a metallic chiral spin liquid and a heavy Fermi liquid in a frustrated lattice. To date, the latter exotic scenario has not been realized. Here, we report the observation of a Chern metal at the onset of the magnetic Kondo breakdown in a frustrated moir\'e Kondo lattice--angle-aligned MoTe2/WSe2 bilayers. The state is compressible and is manifested by a nearly quantized Hall resistance but a finite longitudinal resistance that arises from a bad metallic bulk. The state also separates an itinerant and a heavy Fermi liquid and appears far away from the band inversion critical point of the material, thus ruling out its origin from simply doping a Chern insulator. We demonstrate the presence of a chiral edge state by nonlocal transport measurements and current-induced quantum anomalous Hall breakdown. Magnetic circular dichroism measurements further reveal a magnetization plateau for the Chern metal before a metamagnetic transition at the Kondo breakdown. Our results open an opportunity for moir\'e engineering of exotic quantum phases of matter through the close interplay between band topology and Kondo interactions.