Huge Figure of Merit, Half-Metallic, and Optical Properties in n-Type CoVSb Heuslerene

Highly transparent indium-free multilayers of TiO2/Cu/TiO2 were obtained by means of annealing. The effects of Cu thickness and annealing temperature on the electrical and optical properties were investigated. The critical thickness of Cu mid-layer with optimal electrical and optical properties was 10 nm, with the figure of merit reaching as high as 5 × 10−3 Ω−1. Partial crystallization of the TiO2 layer enhanced the electrical and optical properties upon annealing. Electrothermal experiments showed that temperatures of more than 100 °C can be reached at a heating rate of 2 °C/s without any damage to the multilayers. The experimental results indicate that reliable transparent TiO2/Cu/TiO2 multilayers can be used for electrothermal application.

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Analysis of Dielectric Waveguide Grating and Fabry–Perot Modes in Elastic Grating in Optical Detection of Ultrasound

Sensors ◽

10.3390/s21124081 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4081

Author(s):

Suejit Pechprasarn ◽

Chayanisa Sukkasem ◽

Phitsini Suvarnaphaet

Keyword(s):

Optical Properties ◽

Dielectric Waveguide ◽

Figure Of Merit ◽

Pressure Range ◽

Optical Filter ◽

Grating Period ◽

Wave Mode ◽

Waveguide Grating ◽

Fabry Perot ◽

Optical Grating

In our previous work, we have demonstrated that dielectric elastic grating can support Fabry–Perot modes and provide embedded optical interferometry to measure ultrasonic pressure. The Fabry–Perot modes inside the grating provide an enhancement in sensitivity and figure of merit compared to thin film-based Fabry–Perot structures. Here, in this paper, we propose a theoretical framework to explain that the elastic grating also supports dielectric waveguide grating mode, in which optical grating parameters control the excitation of the two modes. The optical properties of the two modes, including coupling conditions and loss mechanisms, are discussed. The proposed grating has the grating period in micron scale, which is shorter than the wavelength of the incident ultrasound leading to an ultrasonic scattering. The gap regions in the grating allow the elastic grating thickness to be compressed by the incident ultrasound and coupled to a surface acoustic wave mode. The thickness compression can be measured using an embedded interferometer through one of the optical guided modes. The dielectric waveguide grating is a narrow bandpass optical filter enabling an ultrasensitive mode to sense changes in optical displacement. This enhancement in mechanical and optical properties gives rise to a broader detectable pressure range and figure of merit in ultrasonic detection; the detectable pressure range and figure of merit can be enhanced by 2.7 times and 23 times, respectively, compared to conventional Fabry–Perot structures.

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Ab-Initio Investigation of Strain Effects on the Physical Properties of PdVTe Alloy

Canadian Journal of Physics ◽

10.1139/cjp-2020-0527 ◽

2021 ◽

Author(s):

Khodja Djamila ◽

Djaafri Tayeb ◽

Djaafri Abdelkader ◽

Bendjedid Aicha ◽

Hamada Khelifa ◽

...

Keyword(s):

Optical Properties ◽

Density Of States ◽

Phonon Dispersion ◽

Electronic Band Structure ◽

Debye Model ◽

Full Potential ◽

Electronic Band ◽

Metallic Behavior ◽

Strain Effects ◽

Half Metallic

The investigations of the strain effects on magnetism, elasticity, electronic, optical and thermodynamic properties of PdVTe half-Heusler alloy are carried out using the most accurate methods to electronic band structure, i.e. the full-potential linearized augmented plane wave plus a local orbital (FP-LAPW + lo) approach. The analysis of the band structures and the density of states reveals the Half-metallic behavior with a small indirect band gap Eg of 0.51 eV around the Fermi level for the minority spin channels. The study of magnetic properties led to the predicted value of total magnetic moment µtot = 3µB, which nicely follows the Slater–Pauling rule µtot = Zt -18. Several optical properties are calculated for the first time and the predicted values are in line with the Penn model. It is shown from the imaginary part of the complex dielectric function that the investigated alloy is optically metallic. The variations of thermodynamic parameters calculated using the quasi-harmonic Debye model, accord well with the results predicted by the Debye theory. Moreover, the dynamical stability of the investigated alloy is computed by means of the phonon dispersion curves, the density of states, and the formation energies. Finally, the analysis of the strain effects reveals that PdVTe alloy preserves its ferromagnetic half metallic behavior, it remains mechanically stable, the ionic nature dominates the atomic bonding, and the thermodynamic and the optical properties keep the same features in a large interval of pressure.

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DFT study of elastic, half-metallic and optical properties of Co2V(Al, Ge, Ga and Si) compounds

International Journal of Modern Physics B ◽

10.1142/s0217979217501090 ◽

2017 ◽

Vol 31 (14) ◽

pp. 1750109 ◽

Cited By ~ 3

Author(s):

Heidar Khosravi ◽

Arash Boochani ◽

Golnaz Rasolian ◽

Shahram Solaymani ◽

Sirvan Naderi

Keyword(s):

Optical Properties ◽

Density Functional ◽

Magnetic Moments ◽

Elastic Stability ◽

Metallic Behavior ◽

Functional Theory ◽

Spin Mode ◽

Half Metallic ◽

Lattice Constants ◽

Optical Treatment

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.

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Thermodynamic Phase Diagram, Half-Metallic and Optical Properties of the Zr2TiSi [111] Films Based on DFT

Silicon ◽

10.1007/s12633-019-00307-1 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2165-2178

Author(s):

Nosrat-Ali Vahabzadeh ◽

Arash Boochani ◽

Seyed Mohammad Elahi ◽

Hossein Akbari

Keyword(s):

Phase Diagram ◽

Optical Properties ◽

Half Metallic ◽

Thermodynamic Phase Diagram ◽

Thermodynamic Phase

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High Figure of Merit Optical Buffering in Coupled-Slot Slab Photonic Crystal Waveguide with Ionic Liquid

Nanomaterials ◽

10.3390/nano10091742 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1742

Author(s):

Israa Abood ◽

Sayed Elshahat ◽

Zhengbiao Ouyang

Keyword(s):

Ionic Liquid ◽

Optical Properties ◽

Ionic Liquids ◽

Photonic Crystal ◽

Group Velocity ◽

Figure Of Merit ◽

Transmission Rate ◽

Flat Band ◽

Photonic Crystal Waveguide ◽

The Future

Slow light with adequate low group velocity and wide bandwidth with a flat band of the zero-dispersion area were investigated. High buffering capabilities were obtained in a silicon-polymer coupled-slot slab photonic crystal waveguide (SP-CS-SPCW) with infiltrating slots by ionic liquid. A figure of merit (FoM) around 0.663 with the lowest physical bit length Lbit of 4.6748 µm for each stored bit in the optical communication waveband was gained by appropriately modifying the square air slot length. Posteriorly, by filling the slots with ionic liquid, the Lbit was enhanced to be 4.2817 μm with the highest FoM of 0.72402 in wider transmission bandwidth and ultra-high bit rate in terabit range, which may become useful for the future 6G mobile communication network. Ionic liquids have had a noticeable effect in altering the optical properties of photonic crystals. A polymer was used for the future incorporation of an electro-optic effect in buffers to realize the dynamic controlling of optical properties. Ionic liquids enhanced the transmission rate through optical materials. Additionally, the delay time in the ns-range was achieved, providing longer delay and ultra-low group velocity, which is important for light-matter interaction in light amplifiers and nonlinear devices.

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Magnetic and Magneto-Optical Properties of Al Substituted Bi-RIG Particles Dispersed in a Plastic Binder

MRS Proceedings ◽

10.1557/proc-517-577 ◽

1998 ◽

Vol 517 ◽

Author(s):

T. Hirano ◽

K. Yoshida ◽

Y. Yamazaki ◽

T. Namikawa ◽

M. Kishi

Keyword(s):

Optical Properties ◽

Figure Of Merit ◽

Coating Film ◽

Storage Medium ◽

Coating Films ◽

Al Content ◽

Dispersed Particles ◽

Magnetic Compensation ◽

Nano Size ◽

Annealing Method

AbstractNano-size R2BiAlxFe5-xO12(R: Dy, Gd, Th) particles were prepared with a coprecipitation and annealing method. The coating films of the particles were prepared with a coating technique. The magnetic and magneto-optical properties of the particles and films were investigated. The coercive forceHcof the particles and films was increased and saturation magnetizationMs. dropped with the Al contentx. TheHcof the coating films was about 200 Oe at the compositions of dispersed particles for which theMswas almost zero. These results suggest that the increase was made with magnetic compensation. The BiTb2A10.6Fe4.4O12coating film shows Faraday rotation spectra. The figure of merit of the film is about 0.5 at 520 nm. The coating BiTb2A10.6Fe4.4O12film is one of the candidate materials for a new economical magneto-optical storage medium.

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