Excitonic Chern insulator and kinetic ferromagnetism in MoTe${}_2$/WSe${}_2$ moiré bilayer

Abstract

We propose a new mechanism for quantum anomalous Hall (QAH) effect in the AB stacked MoTe${}_2$/WSe${}_2$ system. Based on the observation that the inter-layer tunneling is suppressed in the AB stacking, we consider a model with two layers coupled through the Coulomb interaction. The moiré lattices of the two layers are shifted to form a honeycomb lattice together. Initially, the system is in a layer-polarized Mott insulator at ${\nu }_T=1$. But with a displacement field, an equal number of holes and electrons are doped into the two layers respectively and they form inter-layer exciton condensation. Through mean field theory, we find p$\pm$ip exciton condensation in a certain parameter regime, which leads to a Chern insulator with Chern number $C=\pm 1$. The valleys are polarized due to the kinetic energy instead of interaction. But the polarization in the two layers can be either the same or opposite depending on small perturbations away from a symmetric point. As a result, both valley polarized and inter-valley coherent (IVC) Chern insulator phases are possible. The latter has the same spin $S_z$ in the two layers.

5 pages, 3 figures

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Cited by in corpus (16)

• Mapping twist-tuned multiband topology in bilayer WSe${}_2$
• Interaction-driven topological phase diagram of twisted bilayer MoTe${}_2$
• Chiral Kondo Lattice in Doped MoTe${}_2$/WSe${}_2$ Bilayers
• 1/4 is the new 1/2 when topology is intertwined with Mottness
• A New Era of Excitonic Insulators
• Polaron spectroscopy of a bilayer excitonic insulator
• Kondo effect and its destruction in hetero-bilayer transition metal dichalcogenides
• Topological Kondo semimetal and insulator in AB-stacked heterobilayer transition metal dichalcogenides
• Majorana zero modes in twisted transition metal dichalcogenides homobilayers
• Berry curvature, spin Hall effect and nonlinear optical response in moiré transition metal dichalcogenide heterobilayers
• Symmetric Wannier states and tight-binding model for quantum spin Hall bands in AB-stacked MoTe${}_2$/WSe${}_2$
• Correlated Topological Mixed-Valence Insulators in Moiré Hetero-Bilayers
• Topological $p_x+i{p}_y$ inter-valley coherent state in Moiré MoTe${}_2$/WSe${}_2$ heterobilayers
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Topological Kondo semimetals emulated in hetero-bilayer transition metal dichalcogenides
• Interplay between topology and electron-electron interactions in the moiré MoTe${}_2$/WSe${}_2$ heterobilayer