scholarly journals First-Principles Study of Thermo-Physical Properties of Pu-Containing Gd2Zr2O7

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 196
Author(s):  
Pengcheng Li ◽  
Fengai Zhao ◽  
Haiyan Xiao ◽  
Haibin Zhang ◽  
Hengfeng Gong ◽  
...  
Keyword(s):  
Physical Properties ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Mechanical And Thermal Properties ◽  
Functional Theory ◽  
Waste Immobilization ◽  
Nuclear Waste Immobilization ◽  
Thermo Physical Properties ◽  
Insight Into

A density functional theory plus Hubbard U method is used to investigate how the incorporation of Pu waste into Gd2Zr2O7 pyrochlore influences its thermo-physical properties. It is found that immobilization of Pu at Gd-site of Gd2Zr2O7 has minor effects on the mechanical and thermal properties, whereas substitution of Pu for Zr-site results in remarkable influences on the structural parameters, elastic moduli, elastic isotropy, Debye temperature and electronic structure. The discrepancy in thermo-physical properties between Gd2−yPuyZr2O7 and Gd2Zr2−yPuyO7 may be a result of their different structural and electronic structures. This study provides a direct insight into the thermo-physical properties of Pu-containing Gd2Zr2O7, which will be important for further investigation of nuclear waste immobilization by pyrochlores.

The tuning effect of the electric field on the physical properties of some typical wurtzite semiconductors

2017 ◽  
Vol 31 (33) ◽  
pp. 1750310 ◽  
Author(s):  
Jia-Ning Li ◽  
San-Lue Hu ◽  
Hao-Yu Dong ◽  
Xiao-Ying Xu ◽  
Jia-Fu Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Physical Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Great Influence ◽  
Semiconductor Materials ◽  
Functional Theory ◽  
The Stability ◽  
Wurtzite Semiconductors

Under the tuning of an external electric field, the variation of the geometric structures and the band gaps of the wurtzite semiconductors ZnS, ZnO, BeO, AlN, SiC and GaN have been investigated by the first-principles method based on density functional theory. The stability, density of states, band structures and the charge distribution have been analyzed under the electric field along (001) and (00[Formula: see text]) directions. Furthermore, the corresponding results have been compared without the electric field. According to our calculation, we find that the magnitude and the direction of the electric field have a great influence on the electronic structures of the wurtzite materials we mentioned above, which induce a phase transition from semiconductor to metal under a certain electric field. Therefore, we can regulate their physical properties of this type of semiconductor materials by tuning the magnitude and the direction of the electric field.

Nano-sized nickel catalyst for deep hydrogenation of lignin monomers and first-principles insight into the catalyst preparation

2017 ◽  
Vol 5 (8) ◽  
pp. 3948-3965 ◽  
Author(s):  
Shi-Chao Qi ◽  
Lu Zhang ◽  
Hisahiro Einaga ◽  
Shinji Kudo ◽  
Koyo Norinaga ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Full Range ◽  
Catalyst Preparation ◽  
Ni Catalyst ◽  
Borohydride Reduction ◽  
Functional Theory ◽  
Pyridine Complex ◽  
Insight Into

A type of nano-sized Ni catalyst supported by ZSM-5 zeolite for the deep hydrogenation of lignin monomers is prepared by borohydride reduction of a Ni2+–pyridine complex in ethanol. The mechanism of the borohydride reduction over the full range from Ni2+ to Ni0 is calculated by applying density functional theory.

First-principles calculations of the structural, elastic, mechanical, electronic and optical properties of monoclinic Hf4CuSi4

2020 ◽  
Vol 34 (06) ◽  
pp. 2050035
Author(s):  
Xia Xu ◽  
Wei Zeng ◽  
Fu-Sheng Liu ◽  
Zheng-Tang Liu ◽  
Qi-Jun Liu
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Elastic Anisotropy ◽  
Structural Parameters ◽  
Functional Theory ◽  
Text Structures ◽  
Structure Density

In this paper, the structural, electronic, elastic, mechanical and optical properties of monoclinic [Formula: see text] are studied using the first-principles density functional theory (DFT). The calculated structural parameters are consistent with the experimental data. The elastic constants of [Formula: see text] structures are calculated, indicating that [Formula: see text] shows mechanical stability and elastic anisotropy. According to the [Formula: see text] and Poisson’s ratio, monoclinic [Formula: see text] shows a brittle manner. The energy band structure, density of states, charge transfers and bond populations are given. And the band structure shows that the material is a metal conductor. Moreover, the optical properties and optical anisotropy of [Formula: see text] are shown and analyzed.

First-Principles Study of the Calcium Insertion in Layered and Non-Layered Phases of Vanadia

MRS Advances ◽  
2018 ◽  
Vol 3 (60) ◽  
pp. 3507-3512 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
First Principles ◽  
Vanadium Dioxide ◽  
Calcium Ion ◽  
Density Functional ◽  
Host Lattice ◽  
Functional Theory ◽  
Suitable Material ◽  
Low Concentrations ◽  
Oxide Phases ◽  
Insight Into

ABSTRACTWe investigate the insertion energetics of Ca at low concentrations in four promising vanadium oxide phases (α and δ vanadium pentoxide (V2O5) polymorphs as well as rutile- (R) and bronze-type (B) vanadium dioxide (VO2)) using density functional theory (DFT). We find α-V2O5 to be the most suitable material for an application as cathode, driven by a stable coordinative environment, while VO2(R) does not exhibit a stable low-concentration CaxVO2 phase due to severe distortions of the host lattice due to the large calcium ion. The results provide insight into the possibility of employing these phases as active cathode materials of Ca-ion batteries.

First-Principles Study on Electronic Structure, Elasticity, Debye Temperature and Anisotropy of Cubic KCaF3

2020 ◽  
Vol 999 ◽  
pp. 109-116
Author(s):  
Xing Liu ◽  
Jia Fu ◽  
Man Man Han ◽  
Kai Xin Sun ◽  
Sheng Li Wei
Keyword(s):  
Electronic Structure ◽  
Debye Temperature ◽  
First Principles ◽  
Density Functional ◽  
Elastic Moduli ◽  
Poisson Ratio ◽  
Structural Parameters ◽  
Functional Material ◽  
Covalent Bonds ◽  
Functional Theory

As a potential functional material in the perovskite family, the KCaF3 on electronic structure, elasticity, Debye temperature and anisotropy are studied based on density functional theory (DFT). Above all, the structural parameters of KCaF3 crystal are optimized. Then the elastic constants and Debye temperature are calculated. The results show that: (1) KCaF3 is composed of covalent bonds, in which the Ca-F bond is stronger than K-F. (2) Ca atom mainly contributes for the electronic properties of KCaF3. (3) The structural parameters of KCaF3 is in fair agreement with the experimental data. (4) The anisotropy of KCaF3 was analyzed from the pure and quasi waves, of which the longitudinal wave velocity in the direction of [100] is the larger than the others two directions ([110] and [111]). Finally, The homogenized elastic moduli (bulk modulus B, shear modulus G, Young's modulus E), Pugh and Poisson ratio, are obtained. This research is meaningful and thus to provides a good theoretical guidance for the design the new ABX3-type material with better performance.

First-principles study of electronic, optical and thermoelectric properties in cubic perovskite materials AgMO3 (M = V, Nb, Ta)

2014 ◽  
Vol 28 (10) ◽  
pp. 1450077 ◽  
Author(s):  
Asif Mahmood ◽  
Shahid M. Ramay ◽  
Hafiz Muhammad Rafique ◽  
Yousef Al-Zaghayer ◽  
Salah Ud-Din Khan
Keyword(s):  
Thermoelectric Properties ◽  
First Principles ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Full Potential ◽  
Electronic Band ◽  
Functional Theory ◽  
Perovskite Materials ◽  
Linearized Augmented Plane Wave

In this paper, first-principles calculations of structural, electronic, optical and thermoelectric properties of AgMO 3 ( M = V , Nb and Ta ) have been carried out using full potential linearized augmented plane wave plus local orbitals method ( FP - LAPW + lo ) and BoltzTraP code within the framework of density functional theory (DFT). The calculated structural parameters are found to agree well with the experimental data, while the electronic band structure indicates that AgNbO 3 and AgTaO 3 are semiconductors with indirect bandgaps of 1.60 eV and 1.64 eV, respectively, between the occupied O 2p and unoccupied d states of Nb and Ta . On the other hand, AgVO 3 is found metallic due to the overlapping behavior of states across the Fermi level. Furthermore, optical properties, such as dielectric function, absorption coefficient, optical reflectivity, refractive index and extinction coefficient of AgNbO 3 and AgTaO 3, are calculated for incident photon energy up to 50 eV. Finally, we calculate thermo power for AgNbO 3 and AgTaO 3 at fixed doping 1019 cm-3. Electron doped thermo power of AgNbO 3 shows significant increase over AgTaO 3 with temperature.

scholarly journals Theoretical Investigation of Structural and Optoelectronic Properties of Ternary Acetylides A2MC2 (A = Li, Na, K) and (M = Te, Pb, Pt)

2020 ◽  
Vol 44 (6) ◽  
pp. 413-419
Author(s):  
Abdelhamid Badaoui ◽  
Maamar Belhadji ◽  
Houari Ameur ◽  
Noureddine Kaid
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Band Gaps ◽  
Optical Parameters ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Wave Technique ◽  
Structural And Optoelectronic Properties ◽  
Pseudo Potential

In this work, the structural and optoelectronic parameters of the ternary bialkali acetylides A2MC2 (A = Li, Na, K) and (M = Te, Pd, Pt) with trigonal structures are investigated. The study is conducted by using the first-principles pseudo-potential plane-wave technique, which is based on the Density Functional Theory (DFT) and integrated in the CASTEP software. A special attention is paid to the Tellurium based compounds, since they are less studied. A satisfactory agreement is reported between our results of the structural parameters and those of the literature. Predictions are performed to determine the values of the band gaps and optical parameters.

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

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.

Structural, Electronic and Optical Properties of High (γ)-Li2BeSiO4: First-Principles Calculations

2011 ◽  
Vol 197-198 ◽  
pp. 567-570
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng ◽  
Hao Tian
Keyword(s):  
Optical Properties ◽  
Chemical Bonding ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Population Analysis ◽  
Functional Theory ◽  
Charge Densities ◽  
Bonding Properties ◽  
Direct Band

We have performed ab-initio total energy calculations using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT) to study structural parameters, electronic structure, chemical bonding and optical properties of orthorhombic Li2BeSiO4. The calculated lattice parameters are in agreement with experimental data. The band structure shows a direct band gap. From the DOS analysis, charge densities and population analysis, electronic and chemical bonding properties have been studied. Furthermore, in order to understand the mechanism of optical transitions of orthorhombic Li2BeSiO4, the complex dielectric functions are calculated and analysed.

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