scholarly journals Nonlinear optical susceptibilities, Raman efficiencies, and electro-optic tensors from first-principles density functional perturbation theory

2005 ◽  
Vol 71 (12) ◽  
Author(s):  
M. Veithen ◽  
X. Gonze ◽  
Ph. Ghosez
Keyword(s):  
Perturbation Theory ◽  
First Principles ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Electro Optic ◽  
Density Functional Perturbation Theory

Hydrogenation as a source of superconductivity in two-dimensional TiB2

2021 ◽  
pp. 2150057
Author(s):  
Hui Wang ◽  
Chen Pan ◽  
Sheng-Yan Wang ◽  
Hong Jiang ◽  
Yin-Chang Zhao ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Vibration Frequency ◽  
First Principles ◽  
Density Functional ◽  
Tensile Strain ◽  
2D Materials ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Density Functional Perturbation Theory ◽  
Potential Applications

Using first-principles calculations based on density functional perturbation theory, we demonstrate hydrogenation-induced superconductivity in monolayer TiB2H. Hydrogen adatoms destroy the Dirac state of monolayer TiB2 and monolayer TiB2H has a high vibration frequency. Monolayer TiB2H is a phonon-mediated superconductor. Monolayer TiB2H has a predicted [Formula: see text] of 8[Formula: see text]K, which further increases under external tensile strain. Thus, this study extends our understanding of superconductivity in two-dimensional (2D) materials and its potential applications.

First-Principles Study of Structural and Vibrational Properties of α-SiO2 under Pressure

2015 ◽  
Vol 775 ◽  
pp. 191-196
Author(s):  
Xiao Wei Lei ◽  
Yong Song ◽  
Kuo Yang ◽  
Hui Zhao
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Infrared Spectra ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Vibrational Properties ◽  
Vibrational Modes ◽  
Density Functional Perturbation Theory ◽  
Good Agreement

Using first principles approach, we present the structural, vibrational and dielectric properties of α-SiO2. The calculations have been carried out within the density functional perturbation theory and linear response formalism using the norm-concerving pseudopotentials and a plane wave basis. All the vibrational modes identified are in good agreement with experiment. The calculated infrared spectra are also in good agreement with available experimental results both for the positions and the intensities of the main peaks. We find that the modes Eu7 and A2u4 splits in two respectively at high hydrostaticpressures. Then we calculate the infrared spectra under high pressure of different orientations. The vibrational modes in different phase transitions are reported and discussed respectively.

First-principle studies of the lattice dynamics of crystals, and related properties

2005 ◽  
Vol 220 (5/6) ◽  
Author(s):  
Xavier Gonze ◽  
Gian-Marco Rignanese ◽  
Razvan Caracas
Keyword(s):  
Perturbation Theory ◽  
First Principles ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Computational Method ◽  
Dielectric Tensor ◽  
Atomic Temperature ◽  
Density Functional Perturbation Theory ◽  
Infra Red ◽  
Temperature Factors

AbstractThe crystal lattice is never rigid. Due to temperature, external fields or pressure, the nuclei vibrate, the lattice distorts, and instabilities can induce phase transitions. We review the basic concepts of density-functional perturbation theory, a computational method especially suited to determine from first-principles the microscopic parameters governing such behaviour. Then, we present the additional formalism leading to the following properties of minerals: the infra-red and Raman spectra; the prediction of (meta)stability or instability of a crystalline phase, based on the phonon spectrum; the computation of thermodynamics quantities like the free energy, entropy, specific heat; the atomic temperature factors. For each property, examples are given. When appropriate, we mention the computation of related properties, like dielectric tensor and Born effective charges that are needed to get infra-red spectra. Finally, we discuss briefly, on one hand, other applications of the density-functional perturbation theory, and, on the other hand, an alternative technique, the finite-difference computation of dynamical matrices.

Strain-Induced Modulations of Electro-Optic and Nonlinear Optical Properties of ZnO: A First-Principles Study

2010 ◽  
Vol 29-32 ◽  
pp. 1803-1808 ◽  
Author(s):  
Chun Li ◽  
Fan Yang ◽  
Wan Lin Guo
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Practical Importance ◽  
Nonlinear Optical Properties ◽  
Dielectric Constants ◽  
Functional Theory ◽  
Zinc Blende ◽  
Electro Optic

Strain-dependent electro-optic constant r33 and nonlinear optical coefficient d33 of ZnO are investigated systematically using density-functional theory based linear-response perturbation method. Miscellaneous properties, such as dielectric constants, elastic constants, piezoelectric coefficients, nonlinear optical coefficients, and electro-optic constants of other II-VI compound semiconductors (both Wurtzite and Zinc-blende structures) are also calculated for comparison with the results of unstrained ZnO. Extensive first-principles calculations show that both r33 and d33 of ZnO decrease almost linearly with increasing strains, which indicates that appropriate compression along the [0001] direction of ZnO could enhance its electro-optic and nonlinear optical properties, while stretching may weaken the corresponding properties. Among the involved Wurtzite structures, ZnO has the highest elastic constant, piezoelectric coefficient and electro-optic constant, showing practical importance.

A theoretical study of the structural and electronic properties of poly(9-vinylcarbazole) interacting with small-diameter single-walled carbon nanotubes

2020 ◽  
Vol 09 (02) ◽  
pp. 2050009
Author(s):  
V. W. Elloh ◽  
V. A. Apalangya ◽  
K. Kan-Dapaah ◽  
G. Gebreyesus ◽  
Abhishek K. Mishra ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Charge Transfer ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Small Diameter ◽  
Time Dependent ◽  
Phonon Modes ◽  
Single Walled Carbon ◽  
Density Functional Perturbation Theory ◽  
Dependent Density

Density functional perturbation theory (DFPT) and time-dependent density functional perturbation theory (TDDFPT) calculations were employed to study the molecular and electronic structures, linear and nonlinear optical properties, optical phonon modes and vibrational properties of the interaction of poly(9-vinylcarbazole) (PVK)–small-diameter single-walled carbon nanotube (SWCNT) composites. Our calculations show that the chemical connection between PVK and SWCNTs is only through the relatively weak [Formula: see text]–[Formula: see text] and [Formula: see text]–H bonds. PVK and SWCNTs have different electron accepting abilities and we believe this is the major factor responsible for the charge transfer processes we observe in the calculations. We notice an increase in polarizability value from 152 a.u. (PVK) to 517 a.u. (PVK–SWCNTs), making the PVK–SWCNT composite an ideal model for applications such as mechanical and optoelectronics. Also, the result of our calculations under the time-dependent density functional perturbation theory hinges on the idea that the large value of the polarizability calculated for our composite model is an attribute which can be inferred to processes of charge transfer. Our finding corroborates the fact that non-covalent functionalization is one of the effective chemical methods by which the nonlinear optical response properties of PVK–SWCNT composite may be enhanced.

Thermoelectric and piezoelectric properties of the predicted AlxIn1−xN composites based on ab initio calculations

2017 ◽  
Vol 19 (36) ◽  
pp. 24613-24625 ◽  
Author(s):  
Yee Hui Robin Chang ◽  
Tiem Leong Yoon ◽  
Thong Leng Lim ◽  
Moi Hua Tuh ◽  
Eong Sheng Goh
Keyword(s):  
Perturbation Theory ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Piezoelectric Properties ◽  
Boltzmann Transport ◽  
Density Functional Perturbation Theory ◽  
Theoretical Investigations ◽  
Piezoelectric Characteristics

Theoretical investigations of the thermoelectric and piezoelectric characteristics in the AlxIn1−xN system have been carried out based on a first principles approach in combination with the semi-classical Boltzmann transport concept and density functional perturbation theory.

Structure–thermodynamics relationship of schoepite from first-principles

2019 ◽  
Vol 21 (46) ◽  
pp. 25569-25576 ◽  
Author(s):  
Philippe F. Weck ◽  
Carlos F. Jové-Colón ◽  
Eunja Kim
Keyword(s):  
Perturbation Theory ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Perturbation Theory ◽  
Relationship Of ◽  
The Relationship

The relationship between the structure and thermodynamic properties of schoepite, an important uranyl phase with formula [(UO2)8O2(OH)12]·12H2O formed upon corrosion of UO2, has been investigated with density functional perturbation theory.

scholarly journals Tunability of High-Dielectric-Constant Materials from First Principles

2002 ◽  
Vol 718 ◽  
Author(s):  
K. M. Rabe
Keyword(s):  
Dielectric Constant ◽  
Perturbation Theory ◽  
First Principles ◽  
Density Functional ◽  
High Dielectric Constant ◽  
Leading Order ◽  
Density Functional Perturbation Theory ◽  
High Dielectric Constant Materials ◽  
High Dielectric ◽  
First Principles Method

AbstractA first-principles method, based on density functional perturbation theory, is presented for computing the leading order tunability of high-dielectric-constant materials.

scholarly journals First-principles analysis of a molecular piezoelectric meta-nitroaniline

RSC Advances ◽  
2018 ◽  
Vol 8 (30) ◽  
pp. 16991-16996 ◽  
Author(s):  
Fu Wang ◽  
Zelin Dai ◽  
Yu Gu ◽  
Xiaomeng Cheng ◽  
Yadong Jiang ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Single Crystal ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Crystal Form ◽  
Density Functional Perturbation Theory

The piezoelectric and elastic properties of a molecular piezoelectric meta-nitroaniline (mNA) in its single-crystal form were investigated in the framework of first-principles density functional perturbation theory (DFPT).

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