scholarly journals Semiclassical approach for excitonic spectrum of Coulomb coupling between two Dirac particles

2021 ◽  
Vol 477 (2251) ◽  
pp. 20210098
Author(s):  
Victor V. Zalipaev ◽  
Vladislav V. Kuidin
Keyword(s):  
Energy Spectrum ◽  
Semiclassical Approximation ◽  
Separation Of Variables ◽  
Energy Eigenvalue ◽  
Transition Metal Dichalcogenides ◽  
Energy Eigenvalues ◽  
Dirac Particles ◽  
Metal Dichalcogenides ◽  
Multiband Model ◽  
Eigenvalue System

The properties of the energy spectrum of excitons in monolayer transition metal dichalcogenides are investigated using a multiband model. In the multiband model, we use the excitonic Hamiltonian in the product base of the Dirac single-particle states at the conduction and valence band edges. Following the separation of variables, we decouple the corresponding energy eigenvalue system of the first-order ODE radial equations rigorously and solve the resulting second-order ODE self-consistently, using the finite difference method, thus we determine the energy eigenvalues of the discrete excitonic spectrum and the corresponding wave functions. We also developed a WKB approach to solve the same spectral problem in semiclassical approximation for the resulting ODE. We compare the results for the energy spectrum and the corresponding eigen-function forms for WS 2 and WSe 2 obtained by means of both methods. We also compare our results for the energy spectrum with other theoretical works for excitons, and with available experimental data.

scholarly journals Screening effect for excitonic spectrum of Coulomb coupling between two Dirac particles

2021 ◽  
Vol 2015 (1) ◽  
pp. 012169
Author(s):  
V. Zalipaev ◽  
V. Kuidin
Keyword(s):  
Energy Spectrum ◽  
Energy Levels ◽  
Energy Eigenvalue ◽  
Transition Metal Dichalcogenides ◽  
Screening Effect ◽  
Dirac Particles ◽  
Pure Coulomb ◽  
Metal Dichalcogenides ◽  
Multiband Model ◽  
Eigenvalue System

Abstract The properties of screening effect for energy spectrum of excitons in monolayer transition metal dichalcogenides are investigated using a multiband model. The excitonic hamiltonian in the product base of the Dirac single-particle is used. The corresponding energy eigenvalue system of the first order ODE (radial equations) was solved using the finite difference method. This enables to determine the energy eigenvalues of the discrete excitonic spectrum and the wave functions. We compare the results for the energy spectrum and the corresponding eigen-functions forms for WS 2 and WSe 2 computed for two different potentials: pure Coulomb and screened Coulomb (Keldysh potential). It is demonstrated that excitonic energy levels for unscreened potential lie dipper, and the corresponding eigen-functions’ forms differ from those obtained for screened one.

scholarly journals Super-resolved Optical Mapping of Reactive Sulfur-Vacancies in Two-Dimensional Transition Metal Dichalcogenides

ACS Nano ◽  
2021 ◽  
Author(s):  
Miao Zhang ◽  
Martina Lihter ◽  
Tzu-Heng Chen ◽  
Michal Macha ◽  
Archith Rayabharam ◽  
...  
Keyword(s):  
Transition Metal ◽  
Optical Mapping ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Metal Dichalcogenides

Highly electroconductive and uniform WS2 film growth by sulfurization of W film using diethyl sulfide

2021 ◽  
Author(s):  
Yoobeen Lee ◽  
Jin Won Jung ◽  
Jin Seok Lee
Keyword(s):  
Transition Metal ◽  
Grain Boundaries ◽  
High Performance ◽  
Film Growth ◽  
Transition Metal Dichalcogenides ◽  
Electronic Systems ◽  
Intrinsic Defects ◽  
Diethyl Sulfide ◽  
Metal Dichalcogenides

The reduction of intrinsic defects, including vacancies and grain boundaries, remains one of the greatest challenges to produce high-performance transition metal dichalcogenides (TMDCs) electronic systems. A deeper comprehension of the...

Enhanced Photocurrent Response Speed in Charge-Density-Wave Phase of TiSe2-Metal Junctions

Nanoscale ◽  
2021 ◽  
Author(s):  
Thayer Walmsley ◽  
Yaqiong Xu
Keyword(s):  
Carrier Mobility ◽  
Density Wave ◽  
Transition Metal Dichalcogenides ◽  
Response Speed ◽  
Charge Carrier Mobility ◽  
Metal Dichalcogenides ◽  
Charge Density Wave Phase ◽  
Large Sheet ◽  
High Charge Carrier Mobility ◽  
Significant Attention

Group IVB transition metal dichalcogenides (TMDCs) have attracted significant attention due to their predicted high charge carrier mobility, large sheet current density, and enhanced thermoelectric power. Here, we investigate the...

scholarly journals VS2 as saturable absorber for Q-switched pulse generation

Nanophotonics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 2569-2576 ◽  
Author(s):  
Lu Li ◽  
Lihui Pang ◽  
Qiyi Zhao ◽  
Yao Wang ◽  
Wenjun Liu
Keyword(s):  
Saturable Absorber ◽  
Nonlinear Optical ◽  
Modulation Depth ◽  
Signal To Noise Ratio ◽  
Transition Metal Dichalcogenides ◽  
Laser Cavity ◽  
Pulse Generation ◽  
High Signal ◽  
Power Pulse ◽  
Metal Dichalcogenides

AbstractTransition metal dichalcogenides have been widely utilized as nonlinear optical materials for laser pulse generation applications. Herein, we study the nonlinear optical properties of a VS2-based optical device and its application as a new saturable absorber (SA) for high-power pulse generation. Few-layer VS2 nanosheets are deposited on the tapered region of a microfiber to form an SA device, which shows a modulation depth of 40.52%. After incorporating the microfiber-VS2 SA into an Er-doped fiber laser cavity, passively Q-switched pulse trains could be obtained with repetition rates varying from 95 to 233 kHz. Under the pump power of 890 mW, the largest output power and shortest pulse duration are measured to be 43 mW and 854 ns, respectively. The high signal-to-noise ratio of 60 dB confirms the excellent stability of the Q-switching state. To the best of our knolowdge, this is the first illustration of using VS2 as an SA. Our experimental results demonstrate that VS2 nanomaterials have a large potential for nonlinear optics applications.

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