Quantum Anomalous Hall Effect from Inverted Charge Transfer Gap

  title={Quantum Anomalous Hall Effect from Inverted Charge Transfer Gap},
  author={Trithep Devakul and Liang Fu},
  journal={Physical Review X},
A general mechanism is presented by which topological physics arises in strongly correlated systems without flat bands. Starting from a charge transfer insulator, topology emerges when the charge transfer energy between the cation and anion is reduced to invert the lower Hubbard band and the spin-degenerate charge transfer band. A universal low-energy theory is developed for the inversion of charge transfer gap in a quantum antiferromagnet. The inverted state is found to be a quantum anomalous… 

Theory of quantum anomalous Hall effect and electric-field-induced phase transition in AB-stacked MoTe2/WSe2 moiré heterobilayers

In this letter, we propose a new mechanism to explain the unexpected quantum anomalous Hall (QAH) effect and the electric-field-induced Mott-to-QAH phase transition without bulk gap closure in

Chiral Kondo Lattice in Doped MoTe$_2$/WSe$_2$ Bilayers

We theoretically study the interplay between magnetism and a heavy Fermi liquid in the AB stacked transition metal dichalcogenide bilayer system MoTe 2 /WSe 2 in the regime in which the Mo layer

Valley-coherent quantum anomalous Hall state in AB-stacked MoTe2/WSe2 bilayers

Moiré materials provide fertile ground for the correlated and topological quantum phenomena. Among them, the quantum anomalous Hall (QAH) effect, in which the Hall resistance is quantized even under

Gate-tunable heavy fermions in a moir\'e Kondo lattice

The Kondo lattice, describing a matrix of local magnetic moments coupled via spin-exchange interactions to itinerant conduction electrons, is a prototype of strongly correlated quantum matter 1–5 .

Multiferroicity and Topology in Twisted Transition Metal Dichalcogenides

Van der Waals heterostructures have recently emerged as an exciting platform for investigating the effects of strong electronic correlations, including various forms of magnetic or electrical orders.

Symmetric Wannier states and tight-binding model for quantum spin Hall bands in AB-stacked MoTe$_2$/WSe$_2$

Motivated by the observation of topological states in AB-stacked MoTe 2 /WSe 2 , we construct the symmetry-adapted Wannier states and tight-binding model for the quantum spin Hall bands in this

Realization of the Haldane Chern insulator in a moir\'e lattice

The Chern insulator displays a quantized Hall effect without Landau levels 1–7 . In a landmark paper in 1988, Haldane showed that a Chern insulator could be realized through complex

Topological Phases in AB-Stacked MoTe_{2}/WSe_{2}: Z_{2} Topological Insulators, Chern Insulators, and Topological Charge Density Waves.

We present a theory on the quantum phase diagram of AB-stacked MoTe_{2}/WSe_{2} using a self-consistent Hartree-Fock calculation performed in the plane-wave basis, motivated by the observation of

Topological $p_x+ip_y$ inter-valley coherent state in Moir\'e MoTe$_2$/WSe$_2$ heterobilayers

Recently, a quantum anomalous Hall (QAH) state was observed in AB stacked moir´e MoTe 2 /WSe 2 heterobilayers at half-filling. More recent layer-resolved magnetic circular dichroism (MCD) measurements

Quantum anomalous Hall effect and electric-field-induced topological phase transition in AB-stacked MoTe${}_2$/WSe${}_2$ moir\'e heterobilayers

We propose a new mechanism to explain the quantum anomalous Hall (QAH) effect and the electric-field-induced topological phase transition in AB-stacked MoTe 2 /WSe 2 moir´e heterobilayers at ν = 1 hole



Quantum spin Hall effect in inverted type-II semiconductors.

Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.

Quantum anomalous Hall effect from intertwined moiré bands.

This study reports the observation of a quantum anomalous Hall effect in AB-stacked MoTe2 /WSe2 moiré heterobilayers and paves the way for discovery of emergent phenomena arising from the combined influence of strong correlation and topology in semiconductor moirÉ materials.

Interaction-Driven Spontaneous Quantum Hall Effect on a Kagome Lattice.

This work unveils an interaction-driven spontaneous quantum Hall effect emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry.

Charge transfer excitations, pair density waves, and superconductivity in moiré materials

Transition metal dichalcogenide (TMD) heterobilayers are a new class of tunable moire systems attracting interest as quantum simulators of strongly-interacting electrons in two dimensions. In

Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides

We report a new class of large-gap quantum spin Hall insulators in two-dimensional transition metal dichalcogenides, namely, MX$_2$ with M=(Mo, W) and X=(S, Se, and Te), whose topological electronic

Quantum spin Hall effect in graphene.

Graphene is converted from an ideal two-dimensional semimetallic state to a quantum spin Hall insulator and the spin and charge conductances in these edge states are calculated and the effects of temperature, chemical potential, Rashba coupling, disorder, and symmetry breaking fields are discussed.

Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells

We show that the quantum spin Hall (QSH) effect, a state of matter with topological properties distinct from those of conventional insulators, can be realized in mercury telluride–cadmium telluride

Crystal field splitting in correlated systems with negative charge-transfer gap

It is demonstrated that at least in this case the influence of the p-d covalency on the total value of the crystal field splitting is stronger than the Coulomb interaction (which would lead to the opposite level order).

Intrinsic quantized anomalous Hall effect in a moiré heterostructure

The observation of a QAH effect in twisted bilayer graphene aligned to hexagonal boron nitride is reported, driven by intrinsic strong interactions, which polarize the electrons into a single spin- and valley-resolved moiré miniband with Chern number C = 1.

Excitonic density wave and spin-valley superfluid in bilayer transition metal dichalcogenide

This work presents a theory of this insulating state as an excitonic density wave due to intervalley electron–hole pairing, and shows that exciton condensation is strongly enhanced by a van Hove singularity near the Fermi level.