scholarly journals DFT-Based Approach Enables Deliberate Tuning of Alloy Nanostructures Plasmonic Properties

Author(s):  
Matej Bubaš ◽  
J. Sancho Parramon

<div>Using DFT we calculated band structures and dielectric functions of multiple binary alloy systems. The obtained data enabled us to elucidate the interconnection between alloy composition, fundamental properties such as band structure and their optical properties. The analysis provides the explanation for the smooth change of optical properties in the UV/VIS range and reveals the appearance of strong optical losses in the IR range due to interband transitions. Since they are present in all alloys but not in pure metals we identify such transitions as an emergent property of alloying. To predict plasmonic properties of different alloy nanostructures we performed electrodynamics simulations based on calculated and experimental dielectric functions. The results showed that that calculations based on the standardly used PBE functional in some cases drastically deviate from experiment-based results, and the calculations with an equally efficient GLLB-SC functional are superior. <br></div>

2021 ◽  
Author(s):  
Matej Bubaš ◽  
J. Sancho Parramon

<div>Using DFT we calculated band structures and dielectric functions of multiple binary alloy systems. The obtained data enabled us to elucidate the interconnection between alloy composition, fundamental properties such as band structure and their optical properties. The analysis provides the explanation for the smooth change of optical properties in the UV/VIS range and reveals the appearance of strong optical losses in the IR range due to interband transitions. Since they are present in all alloys but not in pure metals we identify such transitions as an emergent property of alloying. To predict plasmonic properties of different alloy nanostructures we performed electrodynamics simulations based on calculated and experimental dielectric functions. The results showed that that calculations based on the standardly used PBE functional in some cases drastically deviate from experiment-based results, and the calculations with an equally efficient GLLB-SC functional are superior. <br></div>


2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.


2015 ◽  
Vol 29 (05) ◽  
pp. 1550028 ◽  
Author(s):  
R. Graine ◽  
R. Chemam ◽  
F. Z. Gasmi ◽  
R. Nouri ◽  
H. Meradji ◽  
...  

We carried out ab initio calculations of structural, electronic and optical properties of Indium nitride ( InN ) compound in both zinc blende and wurtzite phases, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). For the exchange and correlation potential, local density approximation (LDA) and generalized gradient approximation (GGA) were used. Moreover, the alternative form of GGA proposed by Engel and Vosko (EV-GGA) and modified Becke–Johnson schemes (mBJ) were also applied for band structure calculations. Ground state properties such as lattice parameter, bulk modulus and its pressure derivative are calculated. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show good agreement with the available data. The calculated band structure shows a direct band gap Γ → Γ. In the optical properties section, several optical quantities are investigated; in particular we have deduced the interband transitions from the imaginary part of the dielectric function.


2007 ◽  
Vol 244 (10) ◽  
pp. 3673-3683 ◽  
Author(s):  
Harun Akkus ◽  
Ali Kazempour ◽  
Hadi Akbarzadeh ◽  
Amirullah M. Mamedov

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