Time-domain signatures of distinct correlated insulators in a moiré superlattice
Abstract Among expanding discoveries of quantum phases in moiré superlattices, correlated insulators stand out as both the most stable and most commonly observed. Despite the central importance of these states in moiré physics, little is known about their underlying nature. Here, we use pump-probe s...
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Nature Portfolio
2025-01-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-024-54886-8 |
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| author | Eric A. Arsenault Yiliu Li Birui Yang Takashi Taniguchi Kenji Watanabe James C. Hone Cory R. Dean Xiaodong Xu X.-Y. Zhu |
| author_facet | Eric A. Arsenault Yiliu Li Birui Yang Takashi Taniguchi Kenji Watanabe James C. Hone Cory R. Dean Xiaodong Xu X.-Y. Zhu |
| author_sort | Eric A. Arsenault |
| collection | DOAJ |
| description | Abstract Among expanding discoveries of quantum phases in moiré superlattices, correlated insulators stand out as both the most stable and most commonly observed. Despite the central importance of these states in moiré physics, little is known about their underlying nature. Here, we use pump-probe spectroscopy to show distinct time-domain signatures of correlated insulators at fillings of one (ν = −1) and two (ν = −2) holes per moiré unit cell in the angle-aligned WSe2/WS2 system. Following photo-doping, we find that the disordering time of the ν = −1 state is independent of excitation density (n ex), as expected from the characteristic phonon response time associated with a polaronic state. In contrast, the disordering time of the ν = −2 state scales with $$1/\sqrt{{{{\boldsymbol{n}}}}_{{\mbox{ex}}}}$$ 1 / n ex , in agreement with plasmonic screening from free holons and doublons. These states display disparate reordering behavior dominated either by first order (ν = −1) or second order (ν = −2) recombination, suggesting the presence of Hubbard excitons and free carrier-like holons/doublons, respectively. Our work delineates the roles of electron–phonon (e–ph) versus electron–electron (e–e) interactions in correlated insulators on the moiré landscape and establishes non-equilibrium responses as mechanistic signatures for distinguishing and discovering quantum phases. |
| format | Article |
| id | doaj-art-a3dee88a6d6c4a3bbba4b81dbfbba58e |
| institution | Kabale University |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
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| series | Nature Communications |
| spelling | doaj-art-a3dee88a6d6c4a3bbba4b81dbfbba58e2025-01-12T12:31:36ZengNature PortfolioNature Communications2041-17232025-01-011611810.1038/s41467-024-54886-8Time-domain signatures of distinct correlated insulators in a moiré superlatticeEric A. Arsenault0Yiliu Li1Birui Yang2Takashi Taniguchi3Kenji Watanabe4James C. Hone5Cory R. Dean6Xiaodong Xu7X.-Y. Zhu8Department of Chemistry, Columbia UniversityDepartment of Chemistry, Columbia UniversityDepartment of Physics, Columbia UniversityResearch Center for Materials Nanoarchitectonics, National Institute for Materials ScienceResearch Center for Electronic and Optical Materials, National Institute for Materials ScienceDepartment of Mechanical Engineering, Columbia UniversityDepartment of Physics, Columbia UniversityDepartment of Physics, University of WashingtonDepartment of Chemistry, Columbia UniversityAbstract Among expanding discoveries of quantum phases in moiré superlattices, correlated insulators stand out as both the most stable and most commonly observed. Despite the central importance of these states in moiré physics, little is known about their underlying nature. Here, we use pump-probe spectroscopy to show distinct time-domain signatures of correlated insulators at fillings of one (ν = −1) and two (ν = −2) holes per moiré unit cell in the angle-aligned WSe2/WS2 system. Following photo-doping, we find that the disordering time of the ν = −1 state is independent of excitation density (n ex), as expected from the characteristic phonon response time associated with a polaronic state. In contrast, the disordering time of the ν = −2 state scales with $$1/\sqrt{{{{\boldsymbol{n}}}}_{{\mbox{ex}}}}$$ 1 / n ex , in agreement with plasmonic screening from free holons and doublons. These states display disparate reordering behavior dominated either by first order (ν = −1) or second order (ν = −2) recombination, suggesting the presence of Hubbard excitons and free carrier-like holons/doublons, respectively. Our work delineates the roles of electron–phonon (e–ph) versus electron–electron (e–e) interactions in correlated insulators on the moiré landscape and establishes non-equilibrium responses as mechanistic signatures for distinguishing and discovering quantum phases.https://doi.org/10.1038/s41467-024-54886-8 |
| spellingShingle | Eric A. Arsenault Yiliu Li Birui Yang Takashi Taniguchi Kenji Watanabe James C. Hone Cory R. Dean Xiaodong Xu X.-Y. Zhu Time-domain signatures of distinct correlated insulators in a moiré superlattice Nature Communications |
| title | Time-domain signatures of distinct correlated insulators in a moiré superlattice |
| title_full | Time-domain signatures of distinct correlated insulators in a moiré superlattice |
| title_fullStr | Time-domain signatures of distinct correlated insulators in a moiré superlattice |
| title_full_unstemmed | Time-domain signatures of distinct correlated insulators in a moiré superlattice |
| title_short | Time-domain signatures of distinct correlated insulators in a moiré superlattice |
| title_sort | time domain signatures of distinct correlated insulators in a moire superlattice |
| url | https://doi.org/10.1038/s41467-024-54886-8 |
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