Elastic properties and plane acoustic velocity of cubic Sr2CaMoO6 and Sr2CaWO6 from first-principles calculations

Abstract The elastic properties and plane acoustic velocity of double perovskite Sr2CaMoO6 and Sr2CaWO6 are investigated with the plane wave pseuedopotential method based on the first-principles density functional theory within the local density approximate (LDA) and the generalized gradient approximation (GGA). The calculations indicate that Sr2CaMoO6 and Sr2CaWO6 respectively have the the Mo-O and W-O stable octahedral structure. The bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν and Debye temperature were calculated based on the elastic constants. The three dimensional plane acoustic velocities and their projection are in calculated for each direction by solving the Christoffel’s equation systematically based on the theory of acoustic waves in anisotropic solids, the result shows of anisotropy of lattice vibration for Sr2CaMoO6 is stronger than Sr2CaWO6.

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THEORETICAL INVESTIGATION OF THE ELASTIC PROPERTIES AND LATTICE DYNAMICS OF THE MgSxSe1-x ALLOY

Modern Physics Letters B ◽

10.1142/s0217984907012621 ◽

2007 ◽

Vol 21 (05) ◽

pp. 249-259 ◽

Cited By ~ 9

Author(s):

K. BOUAMAMA ◽

P. DJEMIA

Keyword(s):

Elastic Properties ◽

First Principles ◽

Lattice Dynamics ◽

Density Functional ◽

Local Density ◽

Lattice Parameter ◽

First Principles Calculations ◽

Virtual Crystal Approximation ◽

Functional Theory ◽

Density Functional Perturbation Theory

Structural and elastic properties as well as lattice dynamics of ternary MgS x Se 1-x alloy have been studied using first-principles calculations. These are done using density functional theory (DFT) and density functional perturbation theory (DFPT) within the local density approximation (LDA) and employing the virtual-crystal approximation (VCA). We found that the lattice parameter, the elastic constants and the phonon frequencies follow a quadratic law in x.

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A first principles study of small Cun clusters based on local-density and generalized-gradient approximations to density functional theory

Computational Materials Science ◽

10.1016/s0927-0256(97)00124-9 ◽

1998 ◽

Vol 10 (1-4) ◽

pp. 463-467 ◽

Cited By ~ 6

Author(s):

Carlo Massobrio ◽

Alfredo Pasquarello ◽

Andrea Dal Corso

Keyword(s):

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Generalized Gradient ◽

Functional Theory ◽

First Principles Study

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Electronic and geometric structure of AuxCuy clusters studied by density functional theory

International Journal of Modern Physics C ◽

10.1142/s0129183114500119 ◽

2014 ◽

Vol 25 (06) ◽

pp. 1450011 ◽

Cited By ~ 4

Author(s):

Y. Kadioglu ◽

O. Üzengi Aktürk ◽

M. Tomak

Keyword(s):

Density Functional Theory ◽

Molecular Orbital ◽

Density Functional ◽

Local Density ◽

Three Dimensional ◽

Binding Energies ◽

Generalized Gradient ◽

Functional Theory ◽

Highest Occupied Molecular Orbital ◽

Lowest Unoccupied Molecular Orbital

We have determined the stable structures of Au Cu n, Au 2 Cu n, Au 3 Cu n and Au x Cu 8-x clusters. It has been observed that Au Cu n, Au 2 Cu n and Au 3 Cu n systems have two-dimensional (2D) structures up to six atoms and they become three-dimensional (3D) afterwards. Au x Cu 8-x clusters favor 3D structures till the Au 7 Cu 1 cluster. We have found a lowest energy isomer of Au 6 Cu 2 from the literature. Bond lengths, binding energies, density of states (DOS), highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) gaps, ionization potential (IP) and electron affinity (EA) have been calculated for these structures using the first principles density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA). Generally, we have observed the overlap between s electrons of Cu and p electrons of Au near the Fermi level. Charge transfers are calculated by using the Löwdin analysis. It is observed that one Cu atom does not significantly modify the clusters which have more gold atoms. It is also seen that these clusters generally have nonmagnetic properties and results are consistent with the hybridization between s and d orbitals of Au in Au x Cu 8-x clusters.

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Research on the Elastic Property of Three New Superhard Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.302.165 ◽

2013 ◽

Vol 302 ◽

pp. 165-169

Author(s):

Feng Li ◽

Qun Hui ◽

Jing Ao ◽

Jin Wang ◽

Chun Mei Li ◽

...

Keyword(s):

First Principles ◽

Density Functional ◽

Local Density ◽

Correlation Effect ◽

Superhard Materials ◽

Generalized Gradient ◽

Functional Theory ◽

Spatial Anisotropy ◽

Plane Wave Method ◽

Exchange Correlation

In this thesis, elastic properties of three BCN superhard materials with different structures are computed by using CASTEP software developed according to the first principles which are based on density functional theory (DFT) and plane wave method. CA-PZ of local density approximation (LDA) and PBE of generalized gradient approximation (GGA) are adopted to describe the exchange-correlation effect between electrons. The results are compared with other findings and c-BN data. Through analysis, it is found that the spatial anisotropy do exist in the Young's modulus of single crystals all three BCN compounds.

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Introduction to First-Principles Electronic Structure Methods: Application to Actinide Materials

MRS Proceedings ◽

10.1557/proc-0893-jj01-01 ◽

2005 ◽

Vol 893 ◽

Author(s):

John E Klepeis

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Condensed Matter ◽

Generalized Gradient ◽

Functional Theory ◽

Augmented Plane Wave ◽

Current Controversy ◽

Electronic Structure Methods

AbstractThe purpose of this paper is to provide an introduction for non-experts to first-principles electronic structure methods that are widely used in the field of condensed-matter physics, including applications to actinide materials. The methods I describe are based on density functional theory (DFT) within the local density approximation (LDA) and the generalized gradient approximation (GGA). In addition to explaining the meaning of this terminology I also describe the underlying theory itself in some detail in order to enable a better understanding of the relative strengths and weaknesses of the methods. I briefly mention some particular numerical implementations of DFT, including the linear muffin-tin orbital (LMTO), linear augmented plane wave (LAPW), and pseudopotential methods, as well as general methodologies that go beyond DFT and specifically address some of the weaknesses of the theory. The last third of the paper is devoted to a few selected applications that illustrate the ideas discussed in the first two-thirds. In particular, I conclude by addressing the current controversy regarding magnetic DFT calculations for actinide materials. Throughout this paper particular emphasis is placed on providing the appropriate background to enable the non-expert to gain a better appreciation of the application of first-principles electronic structure methods to the study of actinide and other materials.

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Electronic, Optical and Vibrational Properties of B3N3H6 from First-Principles Calculations

10.21203/rs.3.rs-467643/v1 ◽

2021 ◽

Author(s):

Yun-Dan Gan ◽

Han Qin ◽

Fu-Sheng Liu ◽

Zheng-Tang Liu ◽

Cheng lu Jiang ◽

...

Keyword(s):

First Principles ◽

Density Functional ◽

Local Density ◽

Structural Parameters ◽

Vibrational Properties ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Conductivity Loss ◽

Good Agreement

Abstract The electronic, optical and vibrational properties of B3N3H6 have been calculated by means of first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B3N3H6 are in good agreement with experimental work. With the band structure and density of states (DOS), we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function and reflectivity. By the contrast, it is found that on the (001) component and (100) component have obvious optical anisotropy. Moreover, the vibrational properties have been obtained and analyzed.

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First-principles investigation of the vibrational properties of 3-tert-butylcyclohexene

Open Physics ◽

10.2478/s11534-009-0167-9 ◽

2010 ◽

Vol 8 (5) ◽

Cited By ~ 1

Author(s):

Katalin Gaál-Nagy

Keyword(s):

First Principles ◽

Density Functional ◽

Local Density ◽

Vibrational Properties ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Density Functional Perturbation Theory ◽

Characteristic Modes ◽

Correlation Potential

AbstractI present a first-principles investigation of the vibrational properties of the chiral molecule 3-tert-butylcyclohexene. The vibrational density of states (vDOS) of the two existing conformers has been calculated ab initio within the framework of density-functional theory and density-functional perturbation theory, using both the local-density approximation and the generalized-gradient approximation for the exchange-correlation potential. The vDOS of the two conformers are very similar. The vDOS has been investigated with respect to contributions of the cyclohexene ring and the tert-butyl group and also regarding the localization of vibrational modes. Additionally, the eigendisplacements of characteristic modes of 3-tert-butylcyclohexene have been analyzed.

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First-principles investigation of the structural and elastic properties of Be12Ti under high pressure

RSC Advances ◽

10.1039/c5ra11249d ◽

2015 ◽

Vol 5 (73) ◽

pp. 59648-59654 ◽

Cited By ~ 8

Author(s):

X. K. Liu ◽

W. Zhou ◽

X. Liu ◽

S. M. Peng

Keyword(s):

Density Functional Theory ◽

High Pressure ◽

Correlation Function ◽

Elastic Properties ◽

First Principles ◽

Density Functional ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Generalized Gradient Approximation

The effects of pressure on the structural and elastic properties of Be12Ti were investigated by the generalized gradient approximation (GGA) with a Perdew–Burke–Ernzerhof (PBE) exchange-correlation function using density-functional theory.

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The structural and elastic properties of TMB4(TM =V,Cr,Mn) under pressure: A first-principles study

International Journal of Modern Physics B ◽

10.1142/s0217979214502026 ◽

2014 ◽

Vol 28 (29) ◽

pp. 1450202 ◽

Cited By ~ 1

Author(s):

Xiao-Long Wu ◽

Xiao-Lin Zhou ◽

Jing Chang

Keyword(s):

Elastic Properties ◽

Density Functional ◽

Mechanical Stability ◽

Local Density ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Wide Pressure Range ◽

G Ratio ◽

Wide Pressure

The structural and elastic properties of 3d transition metal tetraboride TM B4(TM = V , Cr , Mn ) have been studied by using density functional theory (DFT) within the local density approximation (LDA) and generalized gradient approximation (GGA) for exchange-correlation function. Our results are in agreement well with available experimental data and previous theoretical studies. The full elastic constants and bulk shear modulus of TM B4(TM = V , Cr , Mn ) are obtained in the wide pressure range. Results indicated that these phases of TM B4(TM = V , Cr , Mn ) are strongly pressure dependent. And the CrB4in Immm structure is the most ultraincompressible among the considered phases at 0 GPa. By the mechanical stability criteria, it is predicted that these phases of TM B4(TM = V , Cr , Mn ) compounds are stable up to 100 GPa. In addition, the calculated B/G ratio indicated that all the structures of TM B4(TM = V , Cr , Mn ) possess brittle nature in the range of pressure from 0 GPa to 100 GPa except the Pnnm structure of MnB4, which is higher than 1.75, indicating that the Pnnm structure of MnB4is prone to ductility when the pressure is above 73 GPa.

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Insight into Physical and Thermodynamic Properties of X3Ir (X = Ti, V, Cr, Nb and Mo) Compounds Influenced by Refractory Elements: A First-Principles Calculation

Crystals ◽

10.3390/cryst9020104 ◽

2019 ◽

Vol 9 (2) ◽

pp. 104 ◽

Cited By ~ 2

Author(s):

Dong Chen ◽

Jiwei Geng ◽

Yi Wu ◽

Mingliang Wang ◽

Cunjuan Xia

Keyword(s):

Thermodynamic Properties ◽

First Principles ◽

Density Functional ◽

Local Density ◽

First Principles Calculation ◽

Generalized Gradient ◽

Functional Theory ◽

Debye Temperatures ◽

Experimental Parameters ◽

Experimental Values

The effects of refractory metals on physical and thermodynamic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds were investigated using local density approximation (LDA) and generalized gradient approximation (GGA) methods within the first-principles calculations based on density functional theory. The optimized lattice parameters were both in good compliance with the experimental parameters. The GGA method could achieve an improved structural optimization compared to the LDA method, and thus was utilized to predict the elastic, thermodynamic and electronic properties of X3Ir (X = Ti, V, Cr, Nb and Mo) compounds. The calculated mechanical properties (i.e., elastic constants, elastic moduli and elastic anisotropic behaviors) were rationalized and discussed in these intermetallics. For instance, the derived bulk moduli exhibited the sequence of Ti3Ir < Nb3Ir < V3Ir < Cr3Ir < Mo3Ir. This behavior was discussed in terms of the volume of unit cell and electron density. Furthermore, Debye temperatures were derived and were found to show good consistency with the experimental values, indicating the precision of our calculations. Finally, the electronic structures were analyzed to explain the ductile essences in the iridium compounds.

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