Phonon-exciton Interactions in WSe2 under a quantizing magnetic field

Li, Zhipeng; Wang, Tianmeng; Miao, Shengnan; Li, Yunmei; Lu, Zheng; Choi, Jin; Lian, Zhongxu; Meng, Yuze; Blei, Mark; Taniguchi, Takashi; Watanabe, Kenji; Tongay, Sefaattin; Wang, Yao; Smirnov, Dmitry; Zhang, Chuanwei; Shi, Su Fei

doi:10.1038/s41467-020-16934-x

Cited by 23 publications

(14 citation statements)

References 39 publications

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“…The moiré superlattice of the twisted bilayer transitional metal dichalcogenides (TMDCs) can form flat minibands with less stringent requirements, with no magic angle required. In addition, due to the large effective mass [10][11][12] , the kinetic energy is further reduced in twisted bilayer TMDCs 13 . The resulting enhanced Coulomb interaction with respect to the kinetic energy leads to strong interactions that give rise to various exotic correlated insulating states [13][14][15][16][17][18][19][20][21] with high transition temperatures.…”

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confidence: 99%

Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

et al. 2021

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Heterobilayers of transition metal dichalcogenides (TMDCs) can form a moiré superlattice with flat minibands, which enables strong electron interaction and leads to various fascinating correlated states. These heterobilayers also host interlayer excitons in a type-II band alignment, in which optically excited electrons and holes reside on different layers but remain bound by the Coulomb interaction. Here we explore the unique setting of interlayer excitons interacting with strongly correlated electrons, and we show that the photoluminescence (PL) of interlayer excitons sensitively signals the onset of various correlated insulating states as the band filling is varied. When the system is in one of such states, the PL of interlayer excitons is relatively amplified at increased optical excitation power due to reduced mobility, and the valley polarization of interlayer excitons is enhanced. The moiré superlattice of the TMDC heterobilayer presents an exciting platform to engineer interlayer excitons through the periodic correlated electron states.

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confidence: 99%

Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

et al. 2021

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“…This feature, referred to as H1, appears in the MoSe 2 PL spectrum with a linewidth comparable to X 0 . While lower-energy PL sidebands are relatively common in TMDs due to phonon replicas and exciton localization, [44][45][46][47][48] these observations are the first such detection of a higher-energy PL sideband. Detailed temperature-, power-, and spatially-resolved PL mea-surements on multiple heterostructures demonstrate that H1 has an origin consistent with a native exciton state rather than a localized exciton or defect state.…”

Section: Introductionmentioning

confidence: 85%

Charge Density Wave Activated Excitons in TiSe$_2$-MoSe$_2$ Heterostructures

Joshi,

Scharf,

Mazin

et al. 2021

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Layered materials enable the assembly of a new class of heterostructures where latticematching is no longer a requirement. Interfaces in these heterostructures therefore become a fertile ground for unexplored physics as dissimilar phenomena can be coupled via proximity effects. In this article we identify an unexpected photoluminescence (PL) peak when MoSe 2 interacts with TiSe 2 . A series of temperature-dependent and spatially-resolved PL measurements reveal this peak is unique to the TiSe 2 -MoSe 2 interface, higher in energy compared to the neutral exciton, and exhibits exciton-like characteristics. The feature disappears at the TiSe 2 charge density wave transition, suggesting that the density wave plays an important role in the formation of this new exciton. We present several plausible scenarios regarding the origin of this peak that individually capture some aspects of our observations, but cannot fully explain this feature. These results therefore represent a fresh challenge for the theoretical community and provide a fascinating way to engineer excitons through interactions with charge density waves.

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“…As a result, chiral phonons have been attracted great interest in recent years. Combined theoretical and experimental efforts have revealed their important contributions to various optical and excitonic effects in two-dimensional (2D) semiconductors [2,10,11], magneto-optical response in topological semimetals [12], electronic or structural phase transitions [13,14], valley phonon Hall effect [15], and etc [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Chiral phonons in a square lattice

Wang¹,

Li²,

Zhu³

et al. 2021

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Chiral phonons were initially proposed and further verified experimentally in two-dimensional (2D) hexagonal crystal lattices. Many intriguing features brought about by chiral phonons are attributed to the pseudo-angular momenta which are associated with the threefold rotational symmetry of hexagonal lattices. Here, we go beyond the hexagonal crystals and investigate the chiral phonons in systems with fourfold rotational symmetry. We clarify the symmetry requirements for the emergence of chiral phonons in both 2D square lattices and 3D tetragonal lattices. For 2D, the realization of C4 chiral phonons requires the breaking of time-reversal symmetry; while for 3D, they can exist on the C4-invariant path in a chiral tetragonal lattice. These phonons have the advantage that they can be more readily coupled with optical transitions, which facilitates their experimental detection. We demonstrate our idea via model analysis and first-principles calculations of concrete materials, including the MnAs monolayer and the α-cristobalite. Our work reveals chiral phonons beyond the hexagonal lattices and paves the way for further exploration of chiral phonon physics in square/tetragonal materials and metamaterials.

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Phonon-exciton Interactions in WSe2 under a quantizing magnetic field

Cited by 23 publications

References 39 publications

Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

Charge Density Wave Activated Excitons in TiSe$_2$-MoSe$_2$ Heterostructures

Chiral phonons in a square lattice

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