Evidence for Exciton Crystals in a 2D Semiconductor Heterotrilayer

Bai, Yusong; Li, Yiliu; Liu, Song; Guo, Yinjie; Pack, Jordan; Wang, Jue; Dean, Cory R.; Hone, James; Zhu, Xiaoyang

doi:10.1021/acs.nanolett.3c03453

Cited by 16 publications

(6 citation statements)

References 48 publications

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“…The enhanced dipolar/quadrupolar interaction strength can be detected from the photoluminescence of localized IXs in moiré patterns [21,22]. In correlated insulators of IXs [24][25][26][27][28], the dipolar/quadrupolar interaction between IXs leads to blue shifts of their luminescence energies, where the interaction strength can be measured experimentally. In [53] generalized Wigner crystal states under electron fillings of ν = 1/3 and 2/3 have been realized in a WS 2 /WSe 2 moiré pattern.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…The formed IX can have an electric dipole pointing upward or downward, or can be in their coherent superposition which has zero electric dipole but a finite electric quadrupole, see illustrations in figure 3(a). Such quadrupolar excitons have been realized and detected in a series of recent experiments [25,[45][46][47]. In this section, we investigate the effects of 2D dielectric screening on the related dipolar and quadrupolar interactions in trilayer TMDs.…”

Section: Dipolar and Quadrupolar Interactions In Trilayer Tmdsmentioning

confidence: 93%

“…In a homobilayer moiré pattern, it is suggested that the luminescence properties of localized IXs can be substantially changed by the near-neighbor dipolar forces [23]. Such a strong dipolar interaction can also facilitate the formation of correlated insulators of IXs, as being observed in recent experiments [24][25][26][27][28]. In most of the early literatures, the dipolar interactions are approximated by the traditional form applicable in a 3D homogeneous dielectric medium.…”

Section: Introductionmentioning

confidence: 99%

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Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures

Hou,

2024

2D Mater.

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We theoretically examined how the dielectric screening of two-dimensional layered materials affects the dipolar interaction between interlayer excitons in few-layer van der Waals structures. Our analysis indicates that the dipolar interaction is largely enhanced by two-dimensional dielectric screening at an inter-exciton separation of several nanometers or larger. The underlying mechanism can be attributed to the induced-charge densities in layered materials, which give rise to induced-dipole densities at large distances with directions parallel to that of the interlayer exciton. The interaction between quadrupolar excitons in trilayer structures are found to be enhanced even larger, with a magnitude one to two orders stronger than that without 2D dielectric screening. The strengths of these dipolar and quadrupolar interactions can be further tuned by engineering the dielectric environment.

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Section: Summary and Discussionmentioning

confidence: 99%

Section: Dipolar and Quadrupolar Interactions In Trilayer Tmdsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures

Hou,

2024

2D Mater.

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“…In recent experimental works [18][19][20][21][22] IL excitons in symmetric TMDC trilayer Moiré structures have been investigated. The Moiré potential leads to spatially dependent band gaps, exciton energies, and layer hybridization.…”

Section: Optical Properties Of Mos 2 /Ws 2 /Mosmentioning

confidence: 99%

“…Very recently, excitons in symmetric trilayer (A/B/A) vdW heterostructures were measured and interpreted as quadrupolar excitons [18][19][20][21][22]. Such symmetric quadrupolar excitons have previously been studied theoretically and predicted to undergo a quantum phase transition from a repulsive quadrupolar to an attractive staggered dipolar phase as the exciton density is increased [23,24].…”

Section: Introductionmentioning

confidence: 99%

Quadrupolar and dipolar excitons in symmetric trilayer heterostructures: insights from first principles theory

Deilmann,

Sommer Thygesen

2024

2D Mater.

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Excitons in van der Waals heterostructures come in many different forms. In bilayer structures, the electron and hole may be localized on the same layer or they may be separated forming an interlayer (IL) exciton with a finite out-of-plane dipole moment. Using first principles calculations, we investigate the excitons in a symmetric WS2/MoS2/WS2 heterostructure in the presence of a vertical electric field. The excitons exhibit a quadratic Stark shift for low field strengths and a linear Stark shift for stronger fields. This behavior is traced to the coupling of IL excitons with opposite dipole moments, which lead to the formation of quadrupolar excitons at small fields. The formation of quadrupolar excitons is determined by the relative size of the electric field-induced splitting of the dipolar excitons and the coupling between them given by the hole tunneling across the MoS2 layer. For the inverted structure, MoS2/WS2/MoS2, the dipolar excitons are coupled by electron tunneling across the WS2 layer. Because this effect is much weaker, the resulting quadrupolar excitons are more fragile and break at a weaker electric field.

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Enhancement of Interlayer Exciton Emission in a TMDC Heterostructure via a Multi‐Resonant Chirped Microresonator Upto Room Temperature

Palekar,

Rosa,

Heermeier

et al. 2024

Advanced Materials

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We report on multi‐resonance chirped distributed Bragg reflector (DBR) microcavities. These systems are employed to investigate the light‐mater interaction with both intra‐ and inter‐layer excitons of transition metal dichalcogenide (TMDC) bilayer heterostructures. The chirped DBRs consisting of SiO2 and Si3N4 layers of gradually varying thickness exhibit a broad stopband with a width exceeding 600 nm. Importantly, the structures provide multiple resonances across a broad spectral range, which can be matched to resonances of the embedded TMDC heterostructures. Studying cavity‐coupled emission of both intra‐ and inter‐layer excitons from an integrated WSe2/MoSe2 heterostructure in a chirped microcavity system, an enhanced interlayer exciton emission with a Purcell factor of 6.67 ± 1.02 at 4 K is observed. The cavity‐enhanced emission of the interlayer exciton is used to investigate its temperature‐dependent luminescence lifetime of 60 ps at room temperature. The cavity system modestly suppresses intralayer exciton emission by intentional detuning, thereby promoting a higher IX population and enhancing cavity‐coupled interlayer exciton emission. This approach provides an intriguing platform for future studies of energetically distant and confined excitons in different semiconducting materials, which paves the way for various applications such as microlasers and single‐photon sources by enabling precise emission control and utilizing multimode resonance light‐matter interaction.

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Evidence for Exciton Crystals in a 2D Semiconductor Heterotrilayer

Cited by 16 publications

References 48 publications

Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures

Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures

Quadrupolar and dipolar excitons in symmetric trilayer heterostructures: insights from first principles theory

Enhancement of Interlayer Exciton Emission in a TMDC Heterostructure via a Multi‐Resonant Chirped Microresonator Upto Room Temperature

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