Abstract

Consecutive topological phase transitions (TPTs) between strongly correlated electronic phases that differ simultaneously in symmetry breaking and topological order are of fundamental interest in condensed matter physics, yet, rarely realized experimentally. We report two consecutive electric-field–driven TPTs at half filling (ν = 1) in angle-aligned MoTe₂/WSe₂ moiré heterobilayers. With increasing out-of-plane displacement field, a geometrically frustrated Mott insulator evolves into a ferromagnetic quantum anomalous Hall (QAH) Mott insulator, i.e., a spin-polarized topological Mott insulator without an observable charge-gap closure, and subsequently into an antiferromagnetic, valley-coherent Mott insulator (VC-AFM) accompanied by a continuous charge-gap collapse and the emergence of a critical metallic state. Layer-resolved magnetic circular dichroism (MCD), magneto-transport, and compressibility measurements jointly determine the phase diagram. The high-field evolution of the antiferromagnetic state reveals a metamagnetic-like transition at a critical field B*, above which a Chern insulating transport response reappears. Our results establish the MoTe₂/WSe₂ moiré platform as a tunable realization of an extended Kane–Mele–Hubbard model hosting sequential correlation–topology intertwined transitions.

Abstract

Consecutive topological phase transitions (TPTs) between strongly correlated electronic phases that differ simultaneously in symmetry breaking and topological order are of fundamental interest in condensed matter physics, yet, rarely realized experimentally. We report two consecutive electric-field–driven TPTs at half filling (ν = 1) in angle-aligned MoTe₂/WSe₂ moiré heterobilayers. With increasing out-of-plane displacement field, a geometrically frustrated Mott insulator evolves into a ferromagnetic quantum anomalous Hall (QAH) Mott insulator, i.e., a spin-polarized topological Mott insulator without an observable charge-gap closure, and subsequently into an antiferromagnetic, valley-coherent Mott insulator (VC-AFM) accompanied by a continuous charge-gap collapse and the emergence of a critical metallic state. Layer-resolved magnetic circular dichroism (MCD), magneto-transport, and compressibility measurements jointly determine the phase diagram. The high-field evolution of the antiferromagnetic state reveals a metamagnetic-like transition at a critical field B*, above which a Chern insulating transport response reappears. Our results establish the MoTe₂/WSe₂ moiré platform as a tunable realization of an extended Kane–Mele–Hubbard model hosting sequential correlation–topology intertwined transitions.

Abstract

Consecutive topological phase transitions (TPTs) between strongly correlated electronic phases that differ simultaneously in symmetry breaking and topological order are of fundamental interest in condensed matter physics, yet, rarely realized experimentally. We report two consecutive electric-field–driven TPTs at half filling (ν = 1) in angle-aligned MoTe₂/WSe₂ moiré heterobilayers. With increasing out-of-plane displacement field, a geometrically frustrated Mott insulator evolves into a ferromagnetic quantum anomalous Hall (QAH) Mott insulator, i.e., a spin-polarized topological Mott insulator without an observable charge-gap closure, and subsequently into an antiferromagnetic, valley-coherent Mott insulator (VC-AFM) accompanied by a continuous charge-gap collapse and the emergence of a critical metallic state. Layer-resolved magnetic circular dichroism (MCD), magneto-transport, and compressibility measurements jointly determine the phase diagram. The high-field evolution of the antiferromagnetic state reveals a metamagnetic-like transition at a critical field B*, above which a Chern insulating transport response reappears. Our results establish the MoTe₂/WSe₂ moiré platform as a tunable realization of an extended Kane–Mele–Hubbard model hosting sequential correlation–topology intertwined transitions.

Abstract

Consecutive topological phase transitions (TPTs) between strongly correlated electronic phases that differ simultaneously in symmetry breaking and topological order are of fundamental interest in condensed matter physics, yet, rarely realized experimentally. We report two consecutive electric-field–driven TPTs at half filling (ν = 1) in angle-aligned MoTe₂/WSe₂ moiré heterobilayers. With increasing out-of-plane displacement field, a geometrically frustrated Mott insulator evolves into a ferromagnetic quantum anomalous Hall (QAH) Mott insulator, i.e., a spin-polarized topological Mott insulator without an observable charge-gap closure, and subsequently into an antiferromagnetic, valley-coherent Mott insulator (VC-AFM) accompanied by a continuous charge-gap collapse and the emergence of a critical metallic state. Layer-resolved magnetic circular dichroism (MCD), magneto-transport, and compressibility measurements jointly determine the phase diagram. The high-field evolution of the antiferromagnetic state reveals a metamagnetic-like transition at a critical field B*, above which a Chern insulating transport response reappears. Our results establish the MoTe₂/WSe₂ moiré platform as a tunable realization of an extended Kane–Mele–Hubbard model hosting sequential correlation–topology intertwined transitions.