scholarly journals Tailoring exciton dynamics of monolayer transition metal dichalcogenides by interfacial electron-phonon coupling

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhonghui Nie ◽  
Yongliang Shi ◽  
Shuchao Qin ◽  
Yuhan Wang ◽  
Hongzhu Jiang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Phonon Coupling ◽  
Exciton Dynamics ◽  
Electron Phonon Coupling ◽  
Metal Dichalcogenides

scholarly journals Structural phase transition and superconductivity hierarchy in 1T-TaS2 under pressure up to 100 GPa

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Qing Dong ◽  
Quanjun Li ◽  
Shujia Li ◽  
Xuhan Shi ◽  
Shifeng Niu ◽  
...  
Keyword(s):  
Structural Phase ◽  
Transition Metal Dichalcogenides ◽  
Phonon Coupling ◽  
Structural Phase Transitions ◽  
Strong Electron ◽  
Electron Phonon Coupling ◽  
Increasing Trend ◽  
Metal Dichalcogenides ◽  
Dome Shape ◽  
Enhanced Superconductivity

AbstractThe adoption of high pressure not only reinforces the comprehension of the structure and exotic electronic states of transition metal dichalcogenides (TMDs) but also promotes the discovery of intriguing phenomena. Here, 1T-TaS2 was investigated up to 100 GPa, and re-enhanced superconductivity was found with structural phase transitions. The discovered I4/mmm TaS2 presents strong electron–phonon coupling, revealing a good superconductivity of the nonlayered structure. The P–T phase diagram shows a dome shape centered at ~20 GPa, which is attributed to the distortion of the 1T structure. Accompanied by the transition to nonlayered structure above 44.5 GPa, the superconducting critical temperature shows an increasing trend and reaches ~7 K at the highest studied pressure, presenting superior superconductivity compared to the original layered structure. It is unexpected that the pressure-induced re-enhanced superconductivity was observed in TMDs, and the transition from a superconductor with complicated electron-pairing mechanism to a phonon-mediated superconductor would expand the field of pressure-modified superconductivity.

Tunable coupling of terahertz Dirac plasmons and phonons in transition metal dichalcogenide-based van der Waals heterostructures

2D Materials ◽  
2021 ◽  
Author(s):  
Icaro Rodrigues Lavor ◽  
Andrey Chaves ◽  
Francois M Peeters ◽  
Ben Van Duppen
Keyword(s):  
Transition Metal ◽  
Fermi Energy ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Phonon Coupling ◽  
Van Der Waals Heterostructures ◽  
Composition And Structure ◽  
Metal Dichalcogenides ◽  
Tunable Coupling

Abstract Dirac plasmons in graphene hybridize with phonons of transition metal dichalcogenides (TMDs) when the materials are combined in so-called van der Waals heterostructures (vdWh), thus forming surface plasmon-phonon polaritons (SPPPs). The extend to which these modes are coupled depends on the TMD composition and structure, but also on the plasmons' properties. By performing realistic simulations that account for the contribution of each layer of the vdWh separately, we calculate how the strength of plasmon-phonon coupling depends on the number and composition of TMD layers, on the graphene Fermi energy and the specific phonon mode. From this, we present a semiclassical theory that is capable of capturing all relevant characteristics of the SPPPs. We find that it is possible to realize both strong and ultra-strong coupling regimes by tuning graphene's Fermi energy and changing TMD layer number.

scholarly journals Real-time GW-BSE investigations on spin-valley exciton dynamics in monolayer transition metal dichalcogenide

2021 ◽  
Vol 7 (10) ◽  
pp. eabf3759
Author(s):  
Xiang Jiang ◽  
Qijing Zheng ◽  
Zhenggang Lan ◽  
Wissam A. Saidi ◽  
Xinguo Ren ◽  
...  
Keyword(s):  
Transition Metal ◽  
Real Time ◽  
Dominant Role ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Many Body ◽  
Exciton Dynamics ◽  
Time Space ◽  
Comprehensive Picture ◽  
Metal Dichalcogenides

We develop an ab initio nonadiabatic molecular dynamics (NAMD) method based on GW plus real-time Bethe-Salpeter equation (GW + rtBSE-NAMD) for the spin-resolved exciton dynamics. From investigations on MoS2, we provide a comprehensive picture of spin-valley exciton dynamics where the electron-phonon (e-ph) scattering, spin-orbit interaction (SOI), and electron-hole (e-h) interactions come into play collectively. In particular, we provide a direct evidence that e-h exchange interaction plays a dominant role in the fast valley depolarization within a few picoseconds, which is in excellent agreement with experiments. Moreover, there are bright-to-dark exciton transitions induced by e-ph scattering and SOI. Our study proves that e-h many-body effects are essential to understand the spin-valley exciton dynamics in transition metal dichalcogenides and the newly developed GW + rtBSE-NAMD method provides a powerful tool for exciton dynamics in extended systems with time, space, momentum, energy, and spin resolution.

Layer Degree of Freedom for Ultrafast Exciton Dynamics in Transition Metal Dichalcogenides

2021 ◽  
Author(s):  
Santu Kumar Bera ◽  
Megha Shrivastava ◽  
Hanyu Zhang ◽  
E.M. Miller ◽  
Matthew C. Beard ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Degree Of Freedom ◽  
Exciton Dynamics ◽  
Metal Dichalcogenides

Trap-free exciton dynamics in monolayer WS2 via oleic acid passivation

Nanoscale ◽  
2021 ◽  
Author(s):  
Dabin Lin ◽  
Wenjun Ni ◽  
Gagik G. Gurzadyan ◽  
Fangteng Zhang ◽  
Weiren Zhao ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Transition Metal ◽  
Free Exciton ◽  
Transition Metal Dichalcogenides ◽  
Photonic Devices ◽  
Optoelectronic Properties ◽  
Two Dimensional ◽  
Exciton Dynamics ◽  
The Past ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides have attracted tremendous attention in the past few decades due to their attractive optoelectronic properties. However, their widespread utility in photonic devices and components is still...

Straining effects in MoS2 monolayer on nanostructured substrates: temperature-dependent photoluminescence and exciton dynamics

Nanoscale ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 5717-5724 ◽  
Author(s):  
Yaowu Hu ◽  
Feng Zhang ◽  
Michael Titze ◽  
Biwei Deng ◽  
Hebin Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Strain Engineering ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Exciton Dynamics ◽  
Mos2 Monolayer ◽  
Metal Dichalcogenides ◽  
Temperature Dependent Photoluminescence

Strain-engineering of two-dimensional (2D) transition metal dichalcogenides (TMDs) has great potential to alter their electronic and optical properties.

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