Probing the impact of magnetic interactions on the lattice dynamics of two-dimensional Ti2X (X = C, N) MXenes

2018 ◽  
Vol 20 (11) ◽  
pp. 7754-7763 ◽  
Author(s):  
Małgorzata Sternik ◽  
Urszula D. Wdowik
Keyword(s):  
Lattice Dynamics ◽  
Magnetic Interactions ◽  
Two Dimensional ◽  
Phonon Modes ◽  
The Impact ◽  
Raman Active Phonon

Magnetic interactions play an important role in the intensities of the Raman-active phonon modes in Ti2X (X = C, N) monolayers.

scholarly journals Comprehensive Raman study of orthorhombic κ/ε-Ga2O3 and the impact of rotational domains

2021 ◽  
Author(s):  
Benjamin M. Janzen ◽  
Piero Mazzolini ◽  
Roland Gillen ◽  
Vivien F. S. Peltason ◽  
Linus P. Grote ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Perturbation Theory ◽  
Gallium Oxide ◽  
Density Functional ◽  
Phonon Modes ◽  
Micro Raman Spectroscopy ◽  
Density Functional Perturbation Theory ◽  
Raman Study ◽  
The Impact ◽  
Raman Active Phonon

The Raman-active phonon modes of orthorhombic gallium oxide (κ/ε-Ga2O3) are investigated by combination of polarized micro-Raman spectroscopy and density functional perturbation theory (DFPT) calculations.

scholarly journals Topologically protected interface phonons in two-dimensional nanomaterials: hexagonal boron nitride and silicon carbide

Nanoscale ◽  
2018 ◽  
Vol 10 (29) ◽  
pp. 13913-13923 ◽  
Author(s):  
Jin-Wu Jiang ◽  
Bing-Shen Wang ◽  
Harold S. Park
Keyword(s):  
Molecular Dynamics ◽  
Silicon Carbide ◽  
Boron Nitride ◽  
Lattice Dynamics ◽  
Hexagonal Boron Nitride ◽  
Dynamics Analysis ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Dynamics Simulations ◽  
Interface Phonons

We perform both lattice dynamics analysis and molecular dynamics simulations to demonstrate the existence of topologically protected phonon modes in two-dimensional, monolayer hexagonal boron nitride and silicon carbide sheets.

Optical properties and Raman-active phonon modes of two-dimensional honeycomb Zintl phases

2017 ◽  
Vol 5 (43) ◽  
pp. 11259-11266 ◽  
Author(s):  
M. Q. Arguilla ◽  
N. D. Cultrara ◽  
M. R. Scudder ◽  
S. Jiang ◽  
R. D. Ross ◽  
...  
Keyword(s):  
Optical Properties ◽  
Raman Spectra ◽  
Band Gaps ◽  
Stacking Sequence ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Zintl Phases ◽  
Group 13 ◽  
Raman Active Phonon

We study how structure and stacking sequence influences the Raman spectra and band gaps in layered intermetallic Zintl phases comprised from honeycomb sheets of group 13, 14, and 15 elements.

Recent Advances and Need of Green Synthesis in Two-Dimensional Materials for Energy Conversion and Storage Applications

2021 ◽  
Vol 16 ◽  
Author(s):  
Joice Sophia Ponraj ◽  
Muniraj Vignesh Narayanan ◽  
Ranjith Kumar Dharman ◽  
Valanarasu Santiyagu ◽  
Ramalingam Gopal ◽  
...  
Keyword(s):  
Energy Storage ◽  
Green Synthesis ◽  
2D Materials ◽  
Synthesis Method ◽  
Energy Storage And Conversion ◽  
Two Dimensional ◽  
Severe Problem ◽  
Energy Conversion And Storage ◽  
Energy Application ◽  
The Impact

: Increasing energy crisis across the globe requires immediate solutions. Two-dimensional (2D) materials are in great significance because of its application in energy storage and conversion devices but the production process significantly impacts the environment thereby posing a severe problem in the field of pollution control. Green synthesis method provides an eminent way of reduction in pollutants. This article reviews the importance of green synthesis in the energy application sector. The focus of 2D materials like graphene, MoS2, VS2 in energy storage and conversion devices are emphasized based on supporting recent reports. The emerging Li-ion batteries are widely reviewed along with their promising alternatives like Zn, Na, Mg batteries and are featured in detail. The impact of green methods in the energy application field are outlined. Moreover, future outlook in the energy sector is envisioned by proposing an increase in 2D elemental materials research.

scholarly journals The Impact of Vibrational Entropy on the Segregation of Cu to Antiphase Boundaries in Fe3Al

2021 ◽  
Vol 7 (8) ◽  
pp. 108
Author(s):  
Martin Friák ◽  
Miroslav Černý ◽  
Mojmír Šob
Keyword(s):  
Magnetic Moments ◽  
Energy Difference ◽  
Extended Defects ◽  
Vibrational Entropy ◽  
Phonon Modes ◽  
Antiphase Boundaries ◽  
Related Energy ◽  
Quantum Mechanical Study ◽  
Nonlinear Trends ◽  
The Impact

We performed a quantum mechanical study of segregation of Cu atoms toward antiphase boundaries (APBs) in Fe3Al. The computed concentration of Cu atoms was 3.125 at %. The APBs have been characterized by a shift of the lattice along the ⟨001⟩ crystallographic direction. The APB energy turns out to be lower for Cu atoms located directly at the APB interfaces and we found that it is equal to 84 mJ/m2. Both Cu atoms (as point defects) and APBs (as extended defects) have their specific impact on local magnetic moments of Fe atoms (mostly reduction of the magnitude). Their combined impact was found to be not just a simple sum of the effects of each of the defect types. The Cu atoms are predicted to segregate toward the studied APBs, but the related energy gain is very small and amounts to only 4 meV per Cu atom. We have also performed phonon calculations and found all studied states with different atomic configurations mechanically stable without any soft phonon modes. The band gap in phonon frequencies of Fe3Al is barely affected by Cu substituents but reduced by APBs. The phonon contributions to segregation-related energy changes are significant, ranging from a decrease by 16% at T = 0 K to an increase by 17% at T = 400 K (changes with respect to the segregation-related energy difference between static lattices). Importantly, we have also examined the differences in the phonon entropy and phonon energy induced by the Cu segregation and showed their strongly nonlinear trends.

Study on Grinding Force in Two-Dimensional Ultrasonic Grinding Nano-Ceramics

2010 ◽  
Vol 42 ◽  
pp. 204-208 ◽  
Author(s):  
Xiang Dong Li ◽  
Quan Cai Wang
Keyword(s):  
Mathematical Model ◽  
Ultrasonic Vibration ◽  
Contact Time ◽  
Reaction Force ◽  
Grinding Force ◽  
Two Dimensional ◽  
Indentation Fracture ◽  
Ultrasonic Grinding ◽  
The Impact ◽  
Ultrasonic Vibration Assisted Grinding

In this paper, the characteristic of grinding force in two-dimensional ultrasonic vibration assisted grinding nano-ceramic was studied by experiment based on indentation fracture mechanics, and mathematical model of grinding force was established. The study shows that grinding force mainly result from the impact of the grains on the workpiece in ultrasonic grinding, and the pulse power is much larger than normal grinding force. The ultrasonic vibration frequency is so high and the contact time of grains with the workpiece is so short that the pulse force will be balanced by reaction force from workpiece. In grinding workpiece was loaded by the periodical stress field, which accelerates the fatigue fracture.

Analysis of the Impact of Specific Heat Ratio on Two-Dimensional Low Maher Number Nozzle Design

2014 ◽  
Vol 590 ◽  
pp. 546-550
Author(s):  
Zhi Qiang Fan ◽  
Hai Bo Yang ◽  
Fei Zhao ◽  
Rong Zhu ◽  
Dong Bai Sun
Keyword(s):  
Specific Heat ◽  
Supersonic Nozzle ◽  
Two Dimensional ◽  
Nozzle Design ◽  
Scheme Design ◽  
Specific Heat Ratio ◽  
Nozzle Contour ◽  
Ratio Change ◽  
Change Impact ◽  
The Impact

The practical requirements of the project the nozzle entrance temperature is high, the gas specific heat ratio varies greatly, so it must consider the specific heat ratio change impact on two-dimensional nozzle contour design. Divided into consideration specific heat ratio change and not consider two kinds of scheme design of 1.4Ma nozzle profile and build the model using the arc line method, numerical simulation is carried out through the CFD software Fluent, analysis of two kinds of design scheme comparison. The results show that, in the supersonic nozzle at low Maher numbers, two schemes of nozzle design profile similarity, parameters change little flow tube, export the Maher number and the flow quality can meet the design requirements, proof of specific heat ratio has little effect on the design results in the design of the nozzle under the condition of low Maher number.

scholarly journals Study of Thermometry in Two-Dimensional Sb2Te3 from Temperature-Dependent Raman Spectroscopy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Manavendra P. Singh ◽  
Manab Mandal ◽  
K. Sethupathi ◽  
M. S. Ramachandra Rao ◽  
Pramoda K. Nayak
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Temperature Coefficient ◽  
Heat Dissipation ◽  
Peak Position ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Temperature Dependent ◽  
Excellent Candidate ◽  
High Figure

AbstractDiscovery of two-dimensional (2D) topological insulators (TIs) demonstrates tremendous potential in the field of thermoelectric since the last decade. Here, we have synthesized 2D TI, Sb2Te3 of various thicknesses in the range 65–400 nm using mechanical exfoliation and studied temperature coefficient in the range 100–300 K using micro-Raman spectroscopy. The temperature dependence of the peak position and line width of phonon modes have been analyzed to determine the temperature coefficient, which is found to be in the order of 10–2 cm−1/K, and it decreases with a decrease in Sb2Te3 thickness. Such low-temperature coefficient would favor to achieve a high figure of merit (ZT) and pave the way to use this material as an excellent candidate for thermoelectric materials. We have estimated the thermal conductivity of Sb2Te3 flake with the thickness of 115 nm supported on 300-nm SiO2/Si substrate which is found to be ~ 10 W/m–K. The slightly higher thermal conductivity value suggests that the supporting substrate significantly affects the heat dissipation of the Sb2Te3 flake.

Phonon Coupling and Dielectric Response in 2D Semiconductor

NANO ◽  
2021 ◽  
Author(s):  
Arslan Usman ◽  
Abdul Sattar ◽  
Hamid Latif ◽  
Muhammad Imran
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Coupling Mechanism ◽  
Two Dimensional ◽  
Electron Hole ◽  
Exciton Coupling ◽  
Gain Energy ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
The Impact

The impact of phonon and their surrounding environment on exciton and its complexes were investigated in monolayer WSe2 semiconductor. Phonon up-conversion has been studied in past for conventional III–V semiconductors, but its role in two-dimensional layered transition metal dichalcogenides has rarely been explored. We investigated the photoluminescence up-conversion mechanism in WSe2 monolayer and found that a lower energy photon gain energy upto 64[Formula: see text]meV to be up-converted to emission photon at room temperature. Moreover, the phonon-exciton coupling mechanism has also been investigated and the role of dielectric screening has been explored to get complete insight of coulomb’s interaction in these electron-hole pairs. Investigations of charge carrier’s lifetime reveal that boron nitride encapsulated monolayer has shorter recombination time as low as 41 ps as compared to a bare monolayer on SiO2 substrate. These results are very promising for realizing spintronics-based application from two-dimensional layered semiconductors.

Phonons transmission through atomic interface connecting two semi-infinite 2D lattices with different meshes

2021 ◽  
Author(s):  
Smail Sait ◽  
Boualem Bourahla
Keyword(s):  
Lattice Dynamics ◽  
Scattering Matrix ◽  
Model Structure ◽  
Coherent Phonon ◽  
Elastic Coupling ◽  
Phonon Modes ◽  
Coherent Transport ◽  
Coherent Coupling ◽  
Discrete States ◽  
Matching Technique

A calculation of the phonon contribution to the coherent transport between two-dimensional (2D) lattices is presented in this paper. The model structure is obtained by the juxtaposition of semi-infinites square ([Formula: see text] and triangular ([Formula: see text] leads, which thus define the nanojunction [Formula: see text]/[Formula: see text] and its inverse [Formula: see text]/[Formula: see text]. We determine, numerically and by simulation, the 2D interface observables for different values of masses and elastic coupling in the nanojunction zone. The local dynamics and atomic nanojunction response to the microscopic changes, in the interfacial domain, are subjects to our investigation. The theoretical formalism based on the matching technique is applied to describe the lattice dynamics and the evanescent phonon modes, in the two studied 2D interfaces. We mainly analyze the vibration spectra, the coherent phonon transmission/reflection and the phononic transmittance through the interface, as elements of a Landauer–Büttiker type scattering matrix. The obtained results show that the nanojunction domain is an effective phonon splitter and suggest that its characteristics may be controlled by varying its nanometric parameters. The observed fluctuations are due to the coherent coupling between continuum modes and the phonons’ discrete states induced by the connected atomic sites.

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