SIMPLE code: Optical properties with optimal basis functions

Prandini, Gianluca; Galante, Mario; Marzari, Nicola; Umari, Paolo

doi:10.1016/j.cpc.2019.02.016

Cited by 30 publications

(24 citation statements)

References 49 publications

(77 reference statements)

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“…:

ω_{p, α β}^{2} = - \frac{4 π e^{2}}{V} \sum_{n, boldnormalk} \frac{\partial f_{n k}}{\partial ε_{n k}} v_{n k}^{α} v_{n k}^{β}

where

v_{n k}^{α} = ℏ^{- 1} \partial ε_{n k} / \partial k_{α}

is the α‐component of the group velocity of the electrons with wave vector k at band n . In this work, the plasma frequency is calculated using the simple code …”

Section: Calculation Detailsmentioning

confidence: 99%

Effect of Mechanical Strain on the Optical Properties of Nodal‐Line Semimetal ZrSiS

Zhou

Руденко

Yuan

2019

Adv Elect Materials

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Optical properties of nodal-line semimetal ZrSiS are studied using first-principles calculations. Frequency-independent optical conductivity is a fingerprint of the infrared optical response in ZrSiS. We find that this characteristic feature is robust with respect to external pressure of up to 10 GPa, yet with the flat region being narrowed with increasing pressure. Upon tensile stress of 2 GPa, the Fermi surface undergoes a topological transition accompanied by a weakening of the interband screening, which reduces the spectral weight of infrared excitations. We also show that the highenergy region is characterized by low-loss plasma excitations at ∼20 eV with essentially anisotropic dispersion. Strongly anisotropic dielectric properties suggest the existence of a hyperbolic regime for plasmons in the deep ultraviolet range. Although the frequencies of high-energy plasmons are virtually unaffected by external pressure, their dispersion can be effectively tuned by strain.

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“…:

ω_{p, α β}^{2} = - \frac{4 π e^{2}}{V} \sum_{n, boldnormalk} \frac{\partial f_{n k}}{\partial ε_{n k}} v_{n k}^{α} v_{n k}^{β}

where

v_{n k}^{α} = ℏ^{- 1} \partial ε_{n k} / \partial k_{α}

is the α‐component of the group velocity of the electrons with wave vector k at band n . In this work, the plasma frequency is calculated using the simple code …”

Section: Calculation Detailsmentioning

confidence: 99%

Effect of Mechanical Strain on the Optical Properties of Nodal‐Line Semimetal ZrSiS

Zhou

Руденко

Yuan

2019

Adv Elect Materials

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“…To the best of our knowledge, for the aforesaid concentration, this is the first time that the anisotropic response is reported for the bulk configuration. The real part of the permittivity (ε 1 ), obtained from the Kramers-Kronig transformation of ε 2 23 , also shows anisotropy (Supplementary Fig. S2(c)).…”

Section: Complex Dielectric Function For Ag-au Alloysmentioning

confidence: 98%

“…33 The optical response of the bimetallic systems are direct dependent on their chemical composition 10,21,36 . For instance, in energy-dependent reflectance measurements one can clear see an 4/17 abrupt reduction of the spectra transitioning from the ultra-violet around 3.5 eV (Ag) to the visible around 2 eV (Au) 23 . For pure Ag and Au, reflectance evaluated with DFT is found to have a slight blue shifted drop (Supplementary Fig.…”

Section: Band Structure and Density Of Statesmentioning

confidence: 99%

“…The advantage of using computational approaches lies in the fact that it is a much faster route to predict materials properties than the traditional fabrication and measurement methods. This has lead to unprecedented development in materials discovery 4,23 . The possibilities of combining materials and properties are numerous, and there are always unexplored aspects of it.…”

Section: Introductionmentioning

confidence: 99%

“…For the Ag 0.50 Au 0.50 alloy, we show that the optical response is anisotropic due to an unbalanced charge distribution among the Au and Ag atoms. Using DFT with the Generalized-Gradient-Approximation (GGA) exchange-correlation functional, we calculate the influence of stoichiometry on the band structures, the density of states, and the energy-dependent permittivity with the independent particle approximation 23 . We observe a drastic difference between the y-direction and the xz-direction of the permittivity in the intraband energy regime.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Anisotropic optical response of gold-silver alloys

Carvalho

Dias

Bezerra

2021

Preprint

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Gold and silver alloys enable novel opportunities for engineering materials with distinct optical responses. Here we investigate the optical properties of gold and silver (Ag x Au 1−x) structures using First-Principle Density Functional Theory (DFT) for gold concentrations varying from 0% up to 100% with steps of 25%. Results of the optical permittivity are analyzed with the independent particle approximation and compared with previously reported theoretical and experimental works. The pure systems and the ones with unbalanced concentrations exhibit isotropic optical responses. The Ag 0.50 Au 0.50 shows an anisotropic response among the y-direction and the xz-direction, mainly in the intraband transition energy range. The anisotropy is elucidated in terms of the d-orbitals density of states and the charge distribution with the structure. The anisotropic optical response can be the origin of the discrepancies among reported experimental results for structures with the same stoichiometry.

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