Nitridoaluminosilicate CaAlSiN3 and its Derivatives - Theory and Experiment

2007 ◽  
Vol 1040 ◽  
Author(s):  
Masayoshi Mikami ◽  
Hiromu Watanabe ◽  
Kyota Uheda ◽  
Naoto Kijima
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
First Principles ◽  
Earth Element ◽  
Natural Extension ◽  
Chemical Properties ◽  
First Principles Calculation ◽  
Experimental Result ◽  
Chemical Compositions ◽  
Virtual Crystal Approximation

AbstractNitridoaluminosilicate MAlSiN3(M: alkaline-earth element) and its derivatives have attracted more and more attention owing to the fact that the material doped with rare-earth element has intense body color and exhibit efficient luminescence under InGaN diode irradiation. In particular, red phosphor, Eu-doped CaAlSiN3 (CASN), has good thermal property of luminescence and sufficient chemical durability for white LED use. Still, for the lineup of various kinds of white color, it is hoped to tune the red luminescence with other physical/chemical properties kept as possible. Thus the derivatives with different chemical compositions have been intensively explored so far. For the feasibility of such chemical composition change, it is necessary to understand its atomic/electronic structure of the unique crystal, which is a distorted AlN-based wurtzite superstructure (Cmc21, No.36) with Al and Si disordered on 8b site and Ca occupying 4a site. Recently, we have performed first-principles band calculation of CASN and clarified the origin of the Al/Si disorder configuration as well as the feasibility of the virtual crystal approximation of heterovalent cations (Al/Si) for the reproducibility of atomic/electronic structure of CASN.[1] As a natural extension of this study, we have investigated some CASN-derivatives to confirm/predict the crystal structure. The VCA allows us to model the superstructure with various chemical compositions quite easily. In this work, we will present two examples of solid-solution, (Ca,Sr)AlSiN3 and CaAlSiN3-Si2N2O. The agreement between experiment and theory appears quite satisfactory. It is emphasized that the crystal structure of SrAlSiN3 has been successfully predicted by first-principles calculation prior to experimental result. The collaboration of experiment and theory promises us ‘gcrystal-engineering’ to develop new nitrides/oxynitrides effectively and efficiently.

Theoretical and experimental studies of Ba2SmTaO6 on crystal structure, electronic structure and optical properties

2018 ◽  
Vol 6 (7) ◽  
pp. 1806-1814
Author(s):  
Jiayi Zheng ◽  
Song Wang ◽  
Lihong Gao ◽  
Zhuang Ma ◽  
Fuchi Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Experimental Studies ◽  
Experimental Methods ◽  
First Principles Calculation

The crystal structure, electronic structure and optical properties of Ba2SmTaO6 have been studied by first-principles calculation, including GGA and GGA+U, as well as by experimental methods.

scholarly journals Strain sensitivity of band structure and electron mobility in perovskite BaSnO3: first-principles calculation

RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14072-14077 ◽  
Author(s):  
Yaqin Wang ◽  
Runqing Sui ◽  
Mei Bi ◽  
Wu Tang ◽  
Sude Ma
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Band Structure ◽  
Electron Mobility ◽  
First Principles ◽  
Structure Calculation ◽  
First Principles Calculation ◽  
Strain Sensitivity ◽  
Biaxial Strain ◽  
Electron Effective Mass

A first-principles electronic structure calculation is utilized to contrastively investigate the crystal structure, band structure, electron effective mass and mobility of perovskite BaSnO3 under hydrostatic and biaxial strain.

scholarly journals Formaldehyde Molecules Adsorption on Zn Doped Monolayer MoS2: A First-Principles Calculation

2021 ◽  
Vol 8 ◽  
Author(s):  
Huili Li ◽  
Ling Fu ◽  
Chaozheng He ◽  
Jinrong Huo ◽  
Houyong Yang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Chemical Properties ◽  
Adsorption Behavior ◽  
First Principles Calculation ◽  
Impurity States ◽  
Adsorption Structure ◽  
Small Clusters

Based on the first principles of density functional theory, the adsorption behavior of H2CO on original monolayer MoS2 and Zn doped monolayer MoS2 was studied. The results show that the adsorption of H2CO on the original monolayer MoS2 is very weak, and the electronic structure of the substrate changes little after adsorption. A new kind of surface single cluster catalyst was formed after Zn doped monolayer MoS2, where the ZnMo3 small clusters made the surface have high selectivity. The adsorption behavior of H2CO on Zn doped monolayer MoS2 can be divided into two situations. When the H-end of H2CO molecule in the adsorption structure is downward, the adsorption energy is only 0.11 and 0.15 eV and the electronic structure of adsorbed substrate changes smaller. When the O-end of H2CO molecule is downward, the interaction between H2CO and the doped MoS2 is strong leading to the chemical adsorption with the adsorption energy of 0.80 and 0.98 eV. For the O-end-down structure, the adsorption obviously introduces new impurity states into the band gap or results in the redistribution of the original impurity states. All of these may lead to the change of the chemical properties of the doped MoS2 monolayer, which can be used to detect the adsorbed H2CO molecules. The results show that the introduction of appropriate dopant may be a feasible method to improve the performance of MoS2 gas sensor.

First-principles study of electronic structure, chemical bonding and elastic properties for new superconductor CaFeAs2

2017 ◽  
Vol 31 (02) ◽  
pp. 1650263
Author(s):  
J. G. Yan ◽  
Z. J. Chen ◽  
G. B. Xu ◽  
Z. Kuang ◽  
T. H. Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculation ◽  
Hard Material ◽  
Dirac Cone ◽  
First Time ◽  
New Superconductor

Using first-principles calculation we investigated the structural, electronic and elastic properties of paramagnetic CaFeAs2. Our results indicated that the density of states (DOS) was dominated predominantly by Fe-3[Formula: see text] states at Fermi levels, and stronger hybridization exists between As1 and As1 atoms. Three hole pockets are formed at [Formula: see text] and Z points, and two electronic pockets are formed at A and E points. The Dirac cone-like bands appear near B and D points. For the first time we calculated the elastic properties and found that CaFeAs2 is a mechanically stable and moderately hard material, it has elastic anisotropy and brittleness, which agrees well with the bonding picture and the calculation of Debye temperature ([Formula: see text]).

Effect of Alloying Elements V, Cr and Ni on the Electronic Structure and Mechanical Properties of FeAl from First-Principles Calculation

2014 ◽  
Vol 887-888 ◽  
pp. 378-383 ◽  
Author(s):  
Yu Chen ◽  
Zheng Jun Yao ◽  
Ping Ze Zhang ◽  
Dong Bo Wei ◽  
Xi Xi Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Valence Bond ◽  
Ternary Alloys ◽  
First Principles Calculation ◽  
Structure Stability ◽  
Alloying Element

The structure stability, mechanical properties and electronic structures of B2 phase FeAl intermetallic compounds and FeAl ternary alloys containing V, Cr or Ni were investigated using first-principles density functional theory calculations. Several models are established. The total energies, cohesive energies, lattice constants, elastic constants, density of states, and the charge densities of Fe8Al8 and Fe8XAl7 ( X=V, Cr, Ni ) are calculated. The stable crystal structures of alloy systems are determined due to the cohesive energy results. The calculated lattice contants of Fe-Al-X ( X= V, Cr, Ni) were found to be related to the atomic radii of the alloy elements. The calculation and analysis of the elastic constants showed that ductility of FeAl alloys was improved by the addition of V, Cr or Ni, the improvement was the highest when Cr was used. The order of the ductility was as follows: Fe8CrAl7 > Fe8NiAl7 > Fe8VAl7 > Fe8Al8. The results of electronic structure analysis showed that FeAl were brittle, mainly due to the orbital hybridization of the s, p and d state electron of Fe and the s and p state electrons of Al, showing typical characteristics of a valence bond. Micro-mechanism for improving ductility of FeAl is that d orbital electron of alloying element is maily involved in hybridization of FeAl, alloying element V, Cr and Ni decrease the directional property in bonding of FeAl.

First Principles Calculation of Geometrical and Electronic Structure of Semiconductor Fe1-xMnxSi2

2011 ◽  
Vol 213 ◽  
pp. 483-486
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Xiao Tian Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principles Calculation ◽  
First Principle ◽  
Substitutional Doping ◽  
Pseudo Potential ◽  
Mn Concentrations

The electronic structure and optical properties of Fe1-xMnxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Mn concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap increase with increasing of Mn.

Repairing single and double atomic vacancies in a C3N monolayer with CO or NO molecules: a first-principles study

2018 ◽  
Vol 20 (19) ◽  
pp. 13517-13527 ◽  
Author(s):  
Dongwei Ma ◽  
Jing Zhang ◽  
Yanan Tang ◽  
Zhaoming Fu ◽  
Zongxian Yang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Magnetic Property ◽  
First Principles ◽  
Chemical Activity ◽  
First Principles Calculation ◽  
First Principles Study ◽  
C And N

Using the first-principles calculation, it is found that the electronic structure, magnetic property and chemical activity of the C3N monolayer can be significantly changed by the C and N single vacancies. Thus, we explored the repairing of the C and N single vacancies in the C3N monolayer by the CO or NO molecules.

Sign in / Sign up

Export Citation Format

Share Document