Luminescent properties and first-principles calculations of (Cr,Ca):YAG crystals

The single crystals of YAG, Cr:YAG and (Cr,Ca):YAG were grown in an optical floating zone furnace. The experimental results show that the optical bandgap of the YAG, (Cr,Ca):YAG and Cr:YAG crystals is about 6.52, 6.31 and 5.50 eV, respectively. The optical bandgap of the (Cr,Ca):YAG crystal is smaller than YAG and larger than Cr:YAG. First-principles calculation results showed that the additions of Cr into YAG will give rise to the change of the electronic states. In a Cr:YAG crystal, the Cr[Formula: see text] impurity introduces a band of 3[Formula: see text] occupied state near the Fermi level, which significantly narrowed the bandgap of Cr:YAG. In a (Cr,Ca):YAG crystal, as the Ca[Formula: see text] ions substitute for the Y[Formula: see text] ions, some of the Cr[Formula: see text] ions will change into Cr[Formula: see text] ions due to the charge balance, which increased the bandgap of the (Cr,Ca):YAG crystal in comparison with that of the Cr:YAG crystal. The calculation is in agreement with the experimental results.

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First-Principles Calculation of Al-Cu-Mg Alloy Strengthening Phase

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1096.109 ◽

2015 ◽

Vol 1096 ◽

pp. 109-113

Author(s):

He Ma ◽

Li Jia Chen ◽

Lian Quan Guo ◽

Li Leng ◽

Lin Lin

Keyword(s):

First Principles ◽

Density Functional ◽

Heat Of Formation ◽

First Principles Calculation ◽

Mg Alloy ◽

First Principles Calculations ◽

Strengthening Phase ◽

Functional Theory ◽

Calculation Results ◽

Mg Content

In this study, equilibrium lattice parameters, heat of formation and cohesive energy of four kinds of typical phases with different structure intermetallic compound in Al-Cu-Mg alloy were investigated by first-principles calculations based on density functional theory via CASTEP software. The calculation results are analyzed and show that ternary strengthening phase Al2CuMg generated first when Mg content is higher, while binary strengthening phase Al2Cu or Al3Cu2 first generated and more stable when Mg content is low in Al-Cu-Mg alloy which indicates that element Cu and Al alloying capacity significantly higher than that of Mg and Al element.

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Optical properties of CeBO3 and CeB3O6 compounds: first-principles calculations and experimental results

Journal of Solid State Chemistry ◽

10.1016/s0022-4596(03)00322-0 ◽

2004 ◽

Vol 177 (1) ◽

pp. 89-100 ◽

Cited By ~ 28

Author(s):

F Goubin ◽

Y Montardi ◽

P Deniard ◽

X Rocquefelte ◽

R Brec ◽

...

Keyword(s):

Optical Properties ◽

First Principles ◽

Experimental Results ◽

First Principles Calculations

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Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

International Journal of Modern Physics B ◽

10.1142/s0217979220502148 ◽

2020 ◽

Vol 34 (25) ◽

pp. 2050214 ◽

Cited By ~ 1

Author(s):

Chang Liu ◽

Enling Li ◽

Tuo Peng ◽

Kaifei Bai ◽

Yanpeng Zheng ◽

...

Keyword(s):

Optical Properties ◽

First Principles ◽

Core Shell ◽

First Principles Calculations ◽

Electronic And Optical Properties ◽

Gan Nanowires ◽

The Core ◽

Light Region ◽

Calculation Results ◽

Shell Nanowires

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

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Pressure effects on mechanical and electronic properties of metallic C14 by first-principles calculation

International Journal of Modern Physics B ◽

10.1142/s0217979219501935 ◽

2019 ◽

Vol 33 (18) ◽

pp. 1950193

Author(s):

Yingjiao Zhou ◽

Qun Wei ◽

Bing Wei ◽

Ruike Yang ◽

Ke Cheng ◽

...

Keyword(s):

High Pressure ◽

Thermodynamic Properties ◽

First Principles ◽

Pressure Range ◽

Phonon Dispersion ◽

Elastic Anisotropy ◽

Acoustic Velocity ◽

Pressure Effects ◽

First Principles Calculation ◽

First Principles Calculations

The elastic constants and phonon dispersion of metallic C[Formula: see text] are calculated by first-principles calculations. The results show that the metallic C[Formula: see text] is mechanically and dynamically stable under high pressure. The variations of G/B ratio, Poisson’s ratio, elastic anisotropy, acoustic velocity and Debye temperature at the pressure range from 0 GPa to 100 GPa are analyzed. The results reveal that by adjusting the pressures the elastic anisotropy and thermodynamic properties could be improved for better applicability.

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Equibiaxial Strained Oxygen Adsorption on Pristine Graphene, Nitrogen/Boron Doped Graphene, and Defected Graphene

Materials ◽

10.3390/ma13214945 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4945

Author(s):

Li-Hua Qu ◽

Xiao-Long Fu ◽

Chong-Gui Zhong ◽

Peng-Xia Zhou ◽

Jian-Min Zhang

Keyword(s):

Electronic Properties ◽

First Principles ◽

Compressive Strain ◽

Oxygen Adsorption ◽

Strain Engineering ◽

Pristine Graphene ◽

First Principles Calculations ◽

Boron Doped ◽

Calculation Results ◽

Doped Graphene

We report first-principles calculations on the structural, mechanical, and electronic properties of O2 molecule adsorption on different graphenes (including pristine graphene (G–O2), N(nitrogen)/B(boron)-doped graphene (G–N/B–O2), and defective graphene (G–D–O2)) under equibiaxial strain. Our calculation results reveal that G–D–O2 possesses the highest binding energy, indicating that it owns the highest stability. Moreover, the stabilities of the four structures are enhanced enormously by the compressive strain larger than 2%. In addition, the band gaps of G–O2 and G–D–O2 exhibit direct and indirect transitions. Our work aims to control the graphene-based structure and electronic properties via strain engineering, which will provide implications for the application of new elastic semiconductor devices.

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Optical and electronic properties of poly(para-phenylene) by first principles calculations and experimental results

10.1109/stsm.1994.836122 ◽

1994 ◽

Author(s):

C. Ambrosch-Draxl ◽

R. Abt ◽

J.A. Majewski ◽

P. Vogl ◽

K.D. Aichholzer ◽

...

Keyword(s):

Electronic Properties ◽

First Principles ◽

Experimental Results ◽

First Principles Calculations ◽

Optical And Electronic Properties

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Switching Mechanism in Resistive Random Access Memory by First-Principles Calculation Using Practical Model Based on Experimental Results

10.7567/ssdm.2016.b-1-04 ◽

2016 ◽

Author(s):

T. Moriyama ◽

T. Yamasaki ◽

S. Hida ◽

T. Ohno ◽

S. Kishida ◽

...

Keyword(s):

First Principles ◽

Random Access ◽

Random Access Memory ◽

Resistive Random Access Memory ◽

Experimental Results ◽

First Principles Calculation ◽

Access Memory ◽

Switching Mechanism ◽

Model Based ◽

Practical Model

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Rate Theory Modeling of Irradiation-induced Phosphorus Segregation in FCC nickel Using First Principles Calculations

MRS Proceedings ◽

10.1557/proc-1125-r07-35 ◽

2008 ◽

Vol 1125 ◽

Author(s):

Ken-ichi Ebihara ◽

Masatake Yamaguchi ◽

Hideo Kaburaki ◽

Yutaka Nishiyama

Keyword(s):

First Principles ◽

Interstitial Site ◽

Theory Model ◽

First Principles Calculation ◽

Rate Theory ◽

Vacancy Mechanism ◽

First Principles Calculations ◽

Phosphorus Segregation ◽

Octahedral Interstitial Site ◽

P Distribution

ABSTRACTWe have evaluated phosphorus (P) segregation in ion-irradiated nickel (Ni) by the rate theory model incorporating the results of first principles calculations. We find from our first principles calculation that the transport of P via the rotation mode of a mixed-dumbbell is unlikely to occur, and the transport coefficient of phosphorus by the vacancy mechanism is much larger than that reported previously. On the basis of our first principles results, we have also proposed to include the effect of free migration of P via the octahedral interstitial site of FCC Ni crystal in the rate theory model. With all these renewed parameters, we have successfully obtained the P distribution in irradiated Ni, which is very close to experiment, by adjusting the effect of P transport by the vacancy mechanism.

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CASTEP Calculation of Surface Energy of α-Al2O3

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.490 ◽

2012 ◽

Vol 512-515 ◽

pp. 490-493 ◽

Cited By ~ 1

Author(s):

Yan Yuan Liang ◽

Da Ming Chen ◽

Jiang Feng Tong

Keyword(s):

First Principles ◽

Growth Habit ◽

First Principles Calculations ◽

Crystal Face ◽

Exchange Correlation ◽

Calculation Results ◽

The Face ◽

Α Al2o3 ◽

Materials Studio ◽

Good Agreement

First principles calculations were run on bulk and the （110）（001）（012）（113） surfaces of α-Al2O3 in order to examine the growth habit of α-Al2O3 crystals.The Materials Studio package was used, specifically the program CASTEP, utilizing Perdew Burke Ernzerh of exchange-correlation pseudo-potentials. The calculation results shows that the ranking of the face energy on different crystal face are E(001)‹ E(113) ‹ E(012) ‹E(110) which is in good agreement with experiment phenomenon observed that the ranking of the growth rates of different crystal faces are V(001) ‹ V(113) ‹ V(012) ‹ V(110).

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Site Preference of Refractory Elements in Ni-Based Single-Crystal Superalloys Alloying with Ru: From First Principles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.554-556.3 ◽

2012 ◽

Vol 554-556 ◽

pp. 3-12

Author(s):

Jian Jun Cui ◽

Fei Sun ◽

Jian Xin Zhang

Keyword(s):

Binding Energy ◽

Single Crystal ◽

First Principles ◽

First Principles Calculation ◽

Partial Density ◽

Site Preference ◽

Strengthening Effect ◽

Mulliken Population ◽

Calculation Results ◽

Partitioning Behavior

A first principles calculation method was used to investigate the site preference of Ruthenium (Ru) at the γ/γ′ interface in Ni-based single-crystal superalloys. The calculation results show that the addition of Ru can decrease the total energy and the binding energy of γ/γ′ interface, which may result in an improved microstructure stability of Ni-based single-crystal superalloys. Moreover, by calculation, it is also found that Ru can stabilize both γ and γ′ phases and have a preference for Ni site at the coherent γ/γ′ interface. When Ru substitutes the central Ni at the γ/γ′ interface, a reverse partitioning of W, Re and Cr occurs; while the partitioning behavior of Mo is not affected. The influence of Ru on the partitioning behavior of W, Re and Cr in γ′-Ni3Al was studied by Dmol3 calculation as well. The calculation results show that W, Re and Cr have a preference for Ni site in γ′- Ni3Al with Ru alloying. When Ru substitutes the central Ni atom, the site preference of W, Re and Cr varies accordingly. Furthermore, electronic structure analysis of γ/γ′ interface and γ′-Ni3Al in terms of Mulliken population and partial density of states (PDOS) was performed to understand the alloying mechanism of Ru in Ni-based single-crystal superalloys. The results show that the strengthening effect of Ru alloying is mainly due to the reduction in binding energy of Ru as well as a p-orbital hybridization between Ru and the host atoms.

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