scholarly journals Spin-textured Chern bands in AB-stacked transition metal dichalcogenide bilayers

2021 ◽  
Vol 118 (36) ◽  
pp. e2112673118
Author(s):  
Yang Zhang ◽  
Trithep Devakul ◽  
Liang Fu
Keyword(s):  
Transition Metal ◽  
Displacement Field ◽  
Anomalous Hall Effect ◽  
Quantum Spin ◽  
Transition Metal Dichalcogenide ◽  
First Principle ◽  
First Principle Calculations ◽  
Hall Effects ◽  
Topological States ◽  
Spin Texture

While transition-metal dichalcogenide (TMD)–based moiré materials have been shown to host various correlated electronic phenomena, topological states have not been experimentally observed until now [T. Li et al., Quantum anomalous Hall effect from intertwined moiré bands. arXiv [Preprint] (2021). https://arxiv.org/abs/2107.01796 (Accessed 5 July 2021)]. In this work, using first-principle calculations and continuum modeling, we reveal the displacement field–induced topological moiré bands in AB-stacked TMD heterobilayer MoTe2/WSe2. Valley-contrasting Chern bands with nontrivial spin texture are formed from interlayer hybridization between MoTe2 and WSe2 bands of nominally opposite spins. Our study establishes a recipe for creating topological bands in AB-stacked TMD bilayers in general, which provides a highly tunable platform for realizing quantum-spin Hall and interaction-induced quantum anomalous Hall effects.

scholarly journals Magic in twisted transition metal dichalcogenide bilayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Trithep Devakul ◽  
Valentin Crépel ◽  
Yang Zhang ◽  
Liang Fu
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Anomalous Hall Effect ◽  
Quantum Spin ◽  
Flat Band ◽  
Magic Angle ◽  
Transition Metal Dichalcogenide ◽  
Strongly Correlated Electron ◽  
Hartree Fock ◽  
The Rich

AbstractThe long-wavelength moiré superlattices in twisted 2D structures have emerged as a highly tunable platform for strongly correlated electron physics. We study the moiré bands in twisted transition metal dichalcogenide homobilayers, focusing on WSe2, at small twist angles using a combination of first principles density functional theory, continuum modeling, and Hartree-Fock approximation. We reveal the rich physics at small twist angles θ < 4∘, and identify a particular magic angle at which the top valence moiré band achieves almost perfect flatness. In the vicinity of this magic angle, we predict the realization of a generalized Kane-Mele model with a topological flat band, interaction-driven Haldane insulator, and Mott insulators at the filling of one hole per moiré unit cell. The combination of flat dispersion and uniformity of Berry curvature near the magic angle holds promise for realizing fractional quantum anomalous Hall effect at fractional filling. We also identify twist angles favorable for quantum spin Hall insulators and interaction-induced quantum anomalous Hall insulators at other integer fillings.

Study of photogenerated exciton dissociation in transition metal dichalcogenide van der Waals heterojunction A2-MWS4: A first-principle study

2021 ◽  
Author(s):  
Hong Cui ◽  
yazhou wang ◽  
Tong Liu ◽  
Yunjian Chen ◽  
Pengyue Shan ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Transition Metal ◽  
Production Efficiency ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenide ◽  
First Principle ◽  
Exciton Dissociation ◽  
Photocatalytic Hydrogen Production

In order to explore the photocatalytic hydrogen production efficiency of MoS2/WSe2 heterostructure (A2-MWS4) as photocatalysts, It is highly desirable to study the photogenerated exciton dissociation related to photocatalysis. The electronic...

The optical properties and carrier mobility in monolayer MH$_3$(M = Co, Rh and Ir)

2021 ◽  
Author(s):  
Yang Yang ◽  
Jimin Shang ◽  
Zijiong Li ◽  
Hong Yan Lu ◽  
Yandong Ma
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Electronic Structures ◽  
Carrier Mobility ◽  
Phonon Dispersion ◽  
Metal Hydrides ◽  
First Principle ◽  
Two Dimensional ◽  
First Principle Calculations ◽  
Transition Metal Hydrides

A new serial of two-dimensional transition metal hydrides MH$_3$ (M = Co, Rh, Ir) is investigated by first principle calculations. Electronic structures, phonon dispersion, optical absorptions, and carrier mobilities are...

scholarly journals Experimental observation of topological Z2 exciton-polaritons in transition metal dichalcogenide monolayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mengyao Li ◽  
Ivan Sinev ◽  
Fedor Benimetskiy ◽  
Tatyana Ivanova ◽  
Ekaterina Khestanova ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Strong Light ◽  
Strongly Coupled ◽  
Exciton Polaritons ◽  
Valley Polarization ◽  
Topological States ◽  
Metal Dichalcogenides ◽  
Quantum Science

AbstractThe rise of quantum science and technologies motivates photonics research to seek new platforms with strong light-matter interactions to facilitate quantum behaviors at moderate light intensities. Topological polaritons (TPs) offer an ideal platform in this context, with unique properties stemming from resilient topological states of light strongly coupled with matter. Here we explore polaritonic metasurfaces based on 2D transition metal dichalcogenides (TMDs) as a promising platform for topological polaritonics. We show that the strong coupling between topological photonic modes of the metasurface and excitons in TMDs yields a topological polaritonic Z2 phase. We experimentally confirm the emergence of one-way spin-polarized edge TPs in metasurfaces integrating MoSe2 and WSe2. Combined with the valley polarization in TMD monolayers, the proposed system enables an approach to engage the photonic angular momentum and valley and spin of excitons, offering a promising platform for photonic/solid-state interfaces for valleytronics and spintronics.

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