Intercell moiré exciton complexes in electron lattices

Wang, Xi; Zhang, Xiaowei; Zhu, Jianping; Park, Heonjoon; Wang, Yingqi; Wang, Chong; Holtzmann, William G.; Taniguchi, Takashi; Watanabe, Kenji; Yan, Jiaqiang; Gamelin, Daniel R.; Yao, Wang; Xiao, Di; Cao, Ting; Xu, Xiaodong

doi:10.1038/s41563-023-01496-2

Cited by 12 publications

(10 citation statements)

References 43 publications

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“…At n=-2, the PL energy exhibits a blueshift. These features correspond to the emergence of insulating states, similar to the previous studies 17,[31][32][33][34] .…”

Section: Evidence Of An Interlayer Mott Insulatorsupporting

confidence: 89%

“…The interlayer excitons, with holes residing in the WSe2 layer and electrons in the WS2 layer (Fig. 1c), interact with the correlated electrons and can be used to read out the transitions at the correlated insulating states 17,[31][32][33][34] . The doping-dependent photoluminescence (PL) spectra in these regions (Figs.…”

Section: Quadrupolar Exciton In Angle-aligned Wse 2 /Ws 2 /B-wse 2 Tr...mentioning

confidence: 99%

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Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Lian,

Chen,

et al. 2023

Nat Commun

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Transition metal dichalcogenide (TMDC) moiré superlattices, owing to the moiré flatbands and strong correlation, can host periodic electron crystals and fascinating correlated physics. The TMDC heterojunctions in the type-II alignment also enable long-lived interlayer excitons that are promising for correlated bosonic states, while the interaction is dictated by the asymmetry of the heterojunction. Here we demonstrate a new excitonic state, quadrupolar exciton, in a symmetric WSe2-WS2-WSe2 trilayer moiré superlattice. The quadrupolar excitons exhibit a quadratic dependence on the electric field, distinctively different from the linear Stark shift of the dipolar excitons in heterobilayers. This quadrupolar exciton stems from the hybridization of WSe2 valence moiré flatbands. The same mechanism also gives rise to an interlayer Mott insulator state, in which the two WSe2 layers share one hole laterally confined in one moiré unit cell. In contrast, the hole occupation probability in each layer can be continuously tuned via an out-of-plane electric field, reaching 100% in the top or bottom WSe2 under a large electric field, accompanying the transition from quadrupolar excitons to dipolar excitons. Our work demonstrates a trilayer moiré system as a new exciting playground for realizing novel correlated states and engineering quantum phase transitions.

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“…At n=-2, the PL energy exhibits a blueshift. These features correspond to the emergence of insulating states, similar to the previous studies 17,[31][32][33][34] .…”

Section: Evidence Of An Interlayer Mott Insulatorsupporting

confidence: 89%

Section: Quadrupolar Exciton In Angle-aligned Wse 2 /Ws 2 /B-wse 2 Tr...mentioning

confidence: 99%

Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Lian,

Chen,

et al. 2023

Nat Commun

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“…These sites possess opposite selection rules but maintain the spin preserving configuration. The observed cross-polarized PL suggests a higher recombination rate at the site by the optical selection rule 18 . Because the site transitions are not observed on the device H1, the emitted light helicity remains unchanged.…”

Section: Resultsmentioning

confidence: 88%

“…Such phenomena are due to the efficient valley-flip scattering as demonstrated in ref. 18 . When , however, we suggest a different mechanism, namely a correlation-driven exciton site transition.…”

Section: Resultsmentioning

confidence: 99%

Correlation-driven nonequilibrium exciton site transition in a WSe2/WS2 moiré supercell

Kim,

Park,

Choi

et al. 2024

Nat Commun

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Moiré superlattices of transition metal dichalcogenides offer a unique platform to explore correlated exciton physics with optical spectroscopy. Whereas the spatially modulated potentials evoke that the exciton resonances are distinct depending on a site in a moiré supercell, there have been no clear demonstration how the moiré excitons trapped in different sites dynamically interact with the doped carriers; so far the exciton-electron dynamic interactions were presumed to be site-dependent. Thus, the transient emergence of nonequilibrium correlations are open questions, but existing studies are limited to steady-state optical measurements. Here we report experimental fingerprints of site-dependent exciton correlations under continuous-wave as well as ultrashort optical excitations. In near-zero angle-aligned WSe2/WS2 heterobilayers, we observe intriguing polarization switching and strongly enhanced Pauli blocking near the Mott insulating state, dictating the dominant correlation-driven effects. When the twist angle is near 60°, no such correlations are observed, suggesting the strong dependence of atomic registry in moiré supercell configuration. Our studies open the door to largely unexplored nonequilibrium correlations of excitons in moiré superlattices.

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“…[1][2][3][4][5] The periodic modulation induced by the moiré pattern on the electronic structures gives rise to the formation of flat bands and localized electronic states [6][7][8][9][10][11] , as well as strongly correlated phases. [2,3,[12][13][14][15] Moreover, the localization pattern of the flat band states resulted from the periodic modulation has a well-defined lattice structure (such as triangular, honeycomb, or rectangular). Therefore, in addition to cold atom gases, moiré superlattices provide another unique platform to realize model quantum Hamiltonians of condensed DOI: 10.1002/adfm.202311814 matter physics on different lattice structures and to explore correlated electron phenomena in a highly controlled and tunable manner.…”

Section: Introductionmentioning

confidence: 99%

Trilayer Moiré Superlattices of MoS₂ as a Simulator for the Ionic Hubbard Model on Honeycomb Lattice

Zhong,

Su,

Kang

2023

Adv Funct Materials

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Recent studies have revealed the potential of 2D moiré superlattices as a condensed matter quantum simulator. The realization of different lattice model Hamiltonians in moiré superlattices has become the focus of researches. Here, it shows that, compared to bilayer moiré superlattices where there is only one interface, the interference between moiré patterns at different interfaces in 2D multilayer structures allows the physical realization of more complicated lattice models. The concept is demonstrated by trilayer moiré superlattices (TMSLs) of MoS2, where it finds that isolated flat moiré bands appear near the valence band edge, and they can be described by the honeycomb lattice ionic Hubbard model. More importantly, the hopping strength, the on‐site Coulomb repulsion, and the staggered potential in the TMSLs are highly tunable through the control of the twist angle, the dielectric environment, and the perpendicular electric field. It is possible to achieve various transitions between distinct quantum phases in the TMSLs, spanning from weak to strong correlation regimes. Therefore, the proposed TMSLs can serve as a good platform to study the strong correlation physics in the honeycomb lattice ionic Hubbard model.

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Intercell moiré exciton complexes in electron lattices

Cited by 12 publications

References 43 publications

Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Correlation-driven nonequilibrium exciton site transition in a WSe2/WS2 moiré supercell

Trilayer Moiré Superlattices of MoS₂ as a Simulator for the Ionic Hubbard Model on Honeycomb Lattice

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Intercell moiré exciton complexes in electron lattices

Cited by 12 publications

References 43 publications

Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Correlation-driven nonequilibrium exciton site transition in a WSe2/WS2 moiré supercell

Trilayer Moiré Superlattices of MoS2 as a Simulator for the Ionic Hubbard Model on Honeycomb Lattice

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Trilayer Moiré Superlattices of MoS₂ as a Simulator for the Ionic Hubbard Model on Honeycomb Lattice