Ab initio study of the mechanical and electronic properties of scheelite-type XWO4(X = Ca, Sr, Ba) compounds

2017 ◽  
Vol 31 (12) ◽  
pp. 1750086 ◽  
Author(s):  
A. Benmakhlouf ◽  
D. Errandonea ◽  
A. Bouhemadou ◽  
A. Bentabet ◽  
S. Maabed ◽  
...  

The structural, mechanical, and electronic properties of scheelite-type CaWO4, SrWO4, and BaWO4 have been investigated using density-functional theory (DFT) within the generalized-gradient approximation (GGA). In particular, we have studied the effect of pressure in the crystal structure, elastic constants [Formula: see text], elastic moduli ([Formula: see text], [Formula: see text] and [Formula: see text]), and elastic anisotropy. We have also investigated the band structure of the three studied compounds and the effect of pressure in their electronic bandgap. The obtained results compare well with experimental results regarding the high-pressure (HP) behavior of the crystal structure. The reported calculations allow us to get a better understanding of effects caused by compression on scheelite-type oxides and to predict the HP response of physical properties of importance for different technological applications.

2015 ◽  
Vol 29 (01) ◽  
pp. 1450256 ◽  
Author(s):  
Wen Huang ◽  
Haichuan Chen

The elastic and thermodynamic properties of Re C 2 (Re = Ho , Nd , Pr ) have been investigated by using the first-principles density functional theory within the generalized gradient approximation. The computed lattice constants of Re C 2 are in agreement with the experimental data. The calculated elastic constants reveal that all compounds are mechanically stable. The shear modulus, Young's modulus, Poisson's ratio σ, the ratio B/G, shear anisotropy and elastic anisotropy are also calculated. Finally, the Vicker hardness, Debye temperature, melting point and thermal conductivity have been predicted.


RSC Advances ◽  
2018 ◽  
Vol 8 (25) ◽  
pp. 13850-13856 ◽  
Author(s):  
Assa Aravindh Sasikala Devi ◽  
Iman S. Roqan

The structural stability and magnetic properties of a grain boundary (GB) formed by two ZnO single crystals oriented at 45° is investigated by density functional theory, using generalized gradient approximation (GGA) with Hubbard parameter (U).


2016 ◽  
Vol 845 ◽  
pp. 247-250
Author(s):  
A.E. Kochengin ◽  
Evgeniy A. Belenkov

Calculations of the structure and electronic properties of crystals composed of graphene layers L6, L4-8, L3-12 and L4-6-12 were performed within the framework of density functional theory (DFT) with generalized gradient approximations (GGA). It was found out, that crystals of the four main types of graphene are to have metallic properties.


2012 ◽  
Vol 26 (29) ◽  
pp. 1250151
Author(s):  
Z. H. YU ◽  
C. Y. LI ◽  
H. Z. LIU

Using the first-principles plane wave pseudopotential method, the structural and electronic properties of intermetallic compound SrLiSb have been studied within generalized gradient approximation in the frame of density functional theory. The calculations of lattice parameters are in well agreement with the available experimental data. The geometry optimization results indicated the compressibility of SrLiSb is anisotropic under high pressure. The energy band structure and density of states of SrLiSb were also calculated, indicating that SrLiSb has an electronic phase transition from direct-gap semiconductor to indirect-gap semiconductor at approximate 8 GPa.


2019 ◽  
Vol 4 (2) ◽  
pp. 72-79
Author(s):  
B. Chettri ◽  
P. K. Patra ◽  
Sunita Srivastava ◽  
Lalhriatzuala ◽  
Lalthakimi Zadeng ◽  
...  

In this work, we have constructed the hydrogenated hexagonal boron nitride (h-BN) by placing hydrogen atom at different surface sites. The possibility of hydrogen adsorption on the BN surface has been estimated by calculating the adsorption energy. The electronic properties were calculated for different hydrogenated BNs. The theoretical calculation was based on the Density Functional Theory (DFT). The electron-exchange energy was treated within the most conventional functional called generalized gradient approximation. The calculated band gap of pure BN is 3.80 eV. The adsorption of two H-atoms at two symmetrical sites of B and N sites reduces the band gap value to 3.5 eV. However, in all other combination the systems show dispersed band at the Fermi level exhibiting conducting behavior. Moreover, from the analysis of band structure and Density Of States we can conclude that, the hydrogenation tunes the band gap of hexagonal boron nitride.


2013 ◽  
Vol 634-638 ◽  
pp. 2545-2549 ◽  
Author(s):  
Jing Kai Yang ◽  
Hong Li Zhao ◽  
Yan Zhu ◽  
Li Ping Zhao ◽  
Jian Li

The structural and electronic properties of Ti-doped SnO2with 6.25 at.% are investigated with the first principle calculations based on the density functional theory within the generalized gradient approximation. The calculation results indicate that the crystal structure of Sn0.9375Ti0.0625O2possesses a smaller volume; the bond length of Ti-O is shorter than that of Sn-O; the relative angle θ change value of Sn-O-Sn→Ti-O-Ti is about 1.07%. Ti-O bond possesses more covalent ingredient and stronger bond energy than Sn-O bond. After the replacement of one Ti atom, O atom bonded with Ti atom possessed fewer electrons, the ratio of charges possessed by Ti atom and O atom dose not agree with the stoichiometry of compound, create more holes at the top of VB of Sn0.9375Ti0.0625O2, and lead to the increase of the conductivity.


2007 ◽  
Vol 121-123 ◽  
pp. 1119-1124
Author(s):  
Feng Bin Liu ◽  
Jia Dao Wang ◽  
Da Rong Chen ◽  
Bing Liu

By means of the density functional theory on the basis of generalized gradient approximation, the reaction paths of the dehydrogenation from the diamond (100) surface was deduced due to the reaction heat. Moreover, the most stable structure of the hydride diamond (100) surface was obtained. The results indicate that the dehydrogenation is easier to take place at the same C-C dimer and forms the parallel geometries. The parallel 1×1:1.5H, 2×1:H and parallel 2×1:0.5H are the intermediate products during the hydrogen desorption process, while, 2×1:H is the most stable structure of the hydride diamond (100) surfaces. The calculated reaction heat is in accordance with the experimental results.


2017 ◽  
Vol 31 (01) ◽  
pp. 1650249
Author(s):  
Diwaker ◽  
Ashwani Kumar

In the present work, we report the structural and the electronic properties of the alloy [Formula: see text] with [Formula: see text] and [Formula: see text]. Ab initio calculations are based upon the density functional theory with generalized gradient approximation and Perdew–Burke–Ernzerhof (PBE) exchange–correlation functional. In our calculations, we found that antimony (Sb) doping in zinc telluride (ZnTe) system introduces some bands which mainly originate from [Formula: see text]- and [Formula: see text]-states of Te and Sb atom and are primarily responsible for [Formula: see text]-type and [Formula: see text]-type conductivity.


2020 ◽  
Vol 22 (26) ◽  
pp. 14712-14719
Author(s):  
Xiaotong Yan ◽  
Yuhua Hou ◽  
Shouhong Zheng ◽  
Youlin Huang ◽  
Wei Li ◽  
...  

Herein, the feasibility of Fe substitution by Ga, Ge and As in Li2FeSiO4 in modulating its structural, mechanical, electrochemical, capacity and electronic properties was systematically studied via first-principles calculations based on density functional theory within the generalized gradient approximation with Hubbard corrections (GGA+U).


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