Crystal Structure Design of Bio-Compatible Piezoelectric Material by using First-principles Calculation

2004 ◽  
Vol 2004.5 (0) ◽  
pp. 93-94
Author(s):  
Yasutomo UETSUJI ◽  
Kouhei IMOTO ◽  
Sadaomi KUMAZAWA ◽  
Kazuyoshi TSUCHIYA ◽  
Eiji NAKAMACHI
2004 ◽  
Vol 2004.17 (0) ◽  
pp. 29-30
Author(s):  
Yasutomo UETSUJI ◽  
Sadaomi KUMAZAWA ◽  
Kazuyoshi TSUCHIYA ◽  
Sei UEDA ◽  
Eiji NAKAMACHI

2015 ◽  
Vol 385 ◽  
pp. 27-31 ◽  
Author(s):  
Hamid Ullah ◽  
Kalsoom Inayat ◽  
S.A .Khan ◽  
S. Mohammad ◽  
A. Ali ◽  
...  

2018 ◽  
Vol 6 (7) ◽  
pp. 1806-1814
Author(s):  
Jiayi Zheng ◽  
Song Wang ◽  
Lihong Gao ◽  
Zhuang Ma ◽  
Fuchi Wang ◽  
...  

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.


2002 ◽  
Vol 753 ◽  
Author(s):  
J-J Gu ◽  
K. Kuwabara ◽  
K. Tanaka ◽  
H. Inui ◽  
M. Yamaguchi ◽  
...  

ABSTRACTThe crystal structure of the defect disilicide formed with Re (ReSi1.75) has been refined by transmission electron microscopy combined with first-principles calculation. The crystal structure is monoclinic with the space group Cm (mc44) due to an ordered arrangement of vacancies on Si sites in the underlying (parent) C11b lattice. The thermoelectric properties of ReSi1.75 are highly anisotropic. Its electrical conduction is of n-type when measure along [001] while it is of p-type when measured along [100]. Although the value of Seebeck coefficient along [100] is moderately high (150–200 μV/K), it is very high along [001] (250–300 μV/K). As a result, a very high value of dimensionless figure of merit (ZT) of 0.7 is achieved at 1073 K when measured along [001].


RSC Advances ◽  
2019 ◽  
Vol 9 (25) ◽  
pp. 14072-14077 ◽  
Author(s):  
Yaqin Wang ◽  
Runqing Sui ◽  
Mei Bi ◽  
Wu Tang ◽  
Sude Ma

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.


2007 ◽  
Vol 1040 ◽  
Author(s):  
Masayoshi Mikami ◽  
Hiromu Watanabe ◽  
Kyota Uheda ◽  
Naoto Kijima

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.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 348
Author(s):  
Loh Kean Ping ◽  
Mohd Ambri Mohamed ◽  
Abhay Kumar Mondal ◽  
Mohamad Fariz Mohamad Taib ◽  
Mohd Hazrie Samat ◽  
...  

The crystal structure, electron charge density, band structure, density of states, and optical properties of pure and strontium (Sr)-doped β-Ga2O3 were studied using the first-principles calculation based on the density functional theory (DFT) within the generalized-gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE). The reason for choosing strontium as a dopant is due to its p-type doping behavior, which is expected to boost the material’s electrical and optical properties and maximize the devices’ efficiency. The structural parameter for pure β-Ga2O3 crystal structure is in the monoclinic space group (C2/m), which shows good agreement with the previous studies from experimental work. Bandgap energy from both pure and Sr-doped β-Ga2O3 is lower than the experimental bandgap value due to the limitation of DFT, which will ignore the calculation of exchange-correlation potential. To counterbalance the current incompatibilities, the better way to complete the theoretical calculations is to refine the theoretical predictions using the scissor operator’s working principle, according to literature published in the past and present. Therefore, the scissor operator was used to overcome the limitation of DFT. The density of states (DOS) shows the hybridization state of Ga 3d, O 2p, and Sr 5s orbital. The bonding population analysis exhibits the bonding characteristics for both pure and Sr-doped β-Ga2O3. The calculated optical properties for the absorption coefficient in Sr doping causes red-shift of the absorption spectrum, thus, strengthening visible light absorption. The reflectivity, refractive index, dielectric function, and loss function were obtained to understand further this novel work on Sr-doped β-Ga2O3 from the first-principles calculation.


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