Moiré alchemy: artificial atoms, Wigner molecules, and emergent Kagome lattice

Reddy, Aidan P.; Devakul, Trithep; Fu, Liang

doi:10.48550/arxiv.2301.00799

Cited by 3 publications

(5 citation statements)

References 34 publications

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“…We thus demonstrated that SBMFT is an excellent approach to narrow down a large parameter space to regions that can potentially host spin-liquid ground states on extended kagome lattice models, without the need to immediately resort to numerically more expensive methods. This might be of great use especially in the rapidly evolving understanding of the microscopic description of TMD moiré bilayers [99,100].…”

Section: Discussionmentioning

confidence: 99%

Schwinger boson study of the J1−J2−J3 kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Rossi,

Motruk,

Rademaker

et al. 2023

Phys. Rev. B

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Schwinger boson mean-field theory is a powerful approach to study frustrated magnetic systems, which allows to distinguish long-range magnetic orders from quantum spin liquid phases, where quantum fluctuations remain strong up to zero temperature. In this paper, we use this framework to study the Heisenberg model on the kagome lattice with up to third-nearest-neighbor interaction and Dzyaloshinskii-Moriya (DM) antisymmetric exchange. This model has been argued to be relevant for the description of transition metal dichalcogenide bilayers in certain parameter regimes, where spin liquids could be realized. By means of the projective symmetry group classification of possible ansätze, we study the effect of the DM interaction at first-nearest neighbor and then compute the J 2 -J 3 phase diagram at different DM angles. We find a phase displaying chiral spin liquid characteristics up to spin S = 0.5, indicating an exceptional stability of the state.

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Section: Discussionmentioning

confidence: 99%

Schwinger boson study of the J1−J2−J3 kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Rossi,

Motruk,

Rademaker

et al. 2023

Phys. Rev. B

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“…This simplified description succeeds in describing several phenomena including incompressible states at fractional fillings known as generalized Wigner crystals. However, as we showed recently, this approach inevitably fails at large moiré period where Coulomb interaction necessarily exceeds the band gap [64].…”

mentioning

confidence: 89%

“…In Ref [64], it was shown that the continuum model Hamiltonian can be characterized by three important length scales: 1) the moiré lattice constant a M , 2) the quantum confinement length ξ 0 ≡ 2 /(mk)…”

mentioning

confidence: 99%

“…• for a range of electron numbers n = 2−9 in Fig 4.In the insets, we show the correspond-ing ground state of classical point charges (determined by minimizing the moiré potential and Coulomb energies). The first clear example of the Wigner molecule occurs at n = 3, where the threefold symmetric crystal field pins an equilateral triangle of charge[64]. In some cases, the classical ground states are unique (N = 3, 4, 6) while, in others, there are several degenerate classical ground states related by point group operations.…”

mentioning

confidence: 99%

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Artificial intelligence for artificial materials: moiré atom

Luo¹,

Reddy²,

Devakul³

et al. 2023

Preprint

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Moiré engineering in atomically thin van der Waals heterostructures creates artificial quantum materials with designer properties. We solve the many-body problem of interacting electrons confined to a moiré superlattice potential minimum (the moiré atom) using a 2D fermionic neural network. We show that strong Coulomb interactions in combination with the anisotropic moiré potential lead to striking "Wigner molecule" charge density distributions observable with scanning tunneling microscopy.

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“…A possible explanation is that holes for 𝜈 > 1 fill a charge transfer band 28 , which can again be described by a t-J model with an enhanced hopping through the physics of Zhang and Rice 39 . An alternative possible explanation is electron-assisted hopping due to Coulomb repulsion within a moiré site that effectively increases the size of the localized orbital and therefore the hopping integral 40 .…”

Section: Main Textmentioning

confidence: 99%

Spin transport of a doped Mott insulator in moiré heterostructures

Wang,

Regan,

et al. 2023

Preprint

Self Cite

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Moiré superlattices of semiconducting transition metal dichalcogenide (TMD) heterobilayers are model systems for investigating strongly correlated electronic phenomena1-12. Specifically, WSe2/WS2 moiré superlattices has emerged as a quantum simulator for the 2D extended Hubbard model1,2, which hosts fascinating correlated charge and spin physics. Experimental studies of charge transport have revealed correlated Mott insulator1,2 and generalized Wigner crystal states1, but spin transport of the moiré heterostructure has not yet been explored. Here, we use spatial- and temporal-resolved circular dichroism spectroscopy to directly image the spin transport as a function of carrier doping and temperature in WSe2/WS2 moiré heterostructures. We observe diffusive spin transport at all hole concentrations at 11 Kelvin, including the Mott insulator at one hole per moiré unit cell, where charge transport is strongly suppressed. At elevated temperatures the spin diffusion constant remains unchanged at the Mott insulator state, but it increases significantly at finite doping away from the Mott state. The doping- and temperature-dependent spin transport can be qualitatively understood using a t-J model, where spins can move via hopping of spin-carrying charges and via the exchange interaction. From the measured spin diffusion constant, we can estimate the effective hopping amplitude t and exchange coupling J in the superlattice. Our results demonstrate opportunities for exploring novel spin physics in correlated electronic systems using TMD moiré superlattices.

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Moiré alchemy: artificial atoms, Wigner molecules, and emergent Kagome lattice

Cited by 3 publications

References 34 publications

Schwinger boson study of the J1−J2−J3 kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Schwinger boson study of the J1−J2−J3 kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

Artificial intelligence for artificial materials: moiré atom

Spin transport of a doped Mott insulator in moiré heterostructures

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