Electronic Structure and Magnetic Properties of Ti-doped ZnO

2009 ◽  
Vol 1183 ◽  
Author(s):  
Soumia Lardjane ◽  
Ghouti Merad ◽  
Houda Imane Faraoun
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Magnetic Semiconductor ◽  
Magnetic Element ◽  
Functional Theory ◽  
Magnetic Structures ◽  
Spintronic Devices ◽  
The Density Functional Theory ◽  
Doped Zno ◽  
Ferromagnetic Ordering

AbstractRecent experiments suggest that Ti doped ZnO can be a promising room temperature dilute magnetic semiconductor (DMS) and a potentially useful material for spintronic devices. Furthermore, the fact that Ti doped ZnO shows ferromagnetic behaviour despite it contains no magnetic element makes this system good candidate for theoretical investigation regarding the controversies about the origin of ferromagnetic ordering in TM-doped ZnO. In this work, the density functional theory (DFT) is used to calculate the electronic and magnetic structures of Ti-doped ZnO. The obtained results are used to discuss the origin of the ferromagnetism, and the contribution of different atoms in the magnetic moment.

FERROMAGNETIC PROPERTIES IN V-DOPED AlN FROM FIRST PRINCIPLES

2012 ◽  
Vol 26 (20) ◽  
pp. 1250132
Author(s):  
G. Y. YAO ◽  
G. H. FAN ◽  
J. H. MA ◽  
S. W. ZHENG ◽  
J. CHEN ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Room Temperature ◽  
Magnetic Semiconductor ◽  
Double Exchange ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Ferromagnetic Ground State

Using the first-principles method based on the density functional theory, we have calculated electronic structure of zinc blende AlN doped with 6.25% of V. The V dopants are found spin polarized and the calculated band structures suggest a 100% polarization of the conduction carriers. The ferromagnetic ground state in V-doped AlN can be explained in terms of double-exchange mechanism, and a Curie temperature above room temperature can be expected. These results suggest that the V-doped AlN may present a promising dilute magnetic semiconductor and find applications in the field of spintronics.

A combined study of the equation of state of monazite-type lanthanum orthovanadate usingin situhigh-pressure diffraction andab initiocalculations

2014 ◽  
Vol 70 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Olga Ermakova ◽  
Javier López-Solano ◽  
Roman Minikayev ◽  
Stefan Carlson ◽  
Agata Kamińska ◽  
...  
Keyword(s):  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Theoretical Data ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Compression Direction ◽  
The Density Functional Theory ◽  
Murnaghan Equation

Lanthanum orthovanadate (LaVO4) is the only stable monazite-type rare-earth orthovanadate. In the present paper the equation of state of LaVO4is studied usingin situhigh-pressure powder diffraction at room temperature, andab initiocalculations within the framework of the density functional theory. The parameters of a second-order Birch–Murnaghan equation of state,i.e.those fitted to the experimental and theoretical data, are found to be in perfect agreement – in particular, the bulk moduli are almost identical, with values of 106 (1) and 105.8 (5) GPa, respectively. In agreement with recent reported experimental data, the compression is shown to be anisotropic. Its nature is comparable to that of some other monazite-type compounds. The softest compression direction is determined.

scholarly journals Investigation of the absorption of CO2 in ionic liquid

2016 ◽  
Vol 29 (1) ◽  
pp. 41-46
Author(s):  
Kalyan Dhar ◽  
Syed Fahim
Keyword(s):  
Ionic Liquid ◽  
Binding Sites ◽  
Density Functional ◽  
Room Temperature ◽  
Minimum Energy ◽  
Environmental Concerns ◽  
Co2 Absorption ◽  
Solvation Model ◽  
Functional Theory ◽  
The Density Functional Theory

Due to environmental concerns, current interest is the development of technologies that may be able to remove CO2 efficiently from exhaust gases and thus avoid its dispersion in the atmosphere. The density functional theory (DFT) calculations with the modern continuum solvation model (IEFPCM-SMD) was used to study the mechanism of CO2 absorption in room temperature ionic liquid such as, [EMIM][BF4] (1-ethyl-3- methylimidazolium tetrafluoroborate). We determine the minimum energy structures and to determine the possible binding sites for CO2 absorption process in [EMIM][BF4]; by comparing the relative minimum energy of [EMIM][BF4] in the presence and absence of CO2.Bangladesh J. Sci. Res. 29(1): 41-46, June-2016

Theoretical Study of the Electronic Structures of Li-Doped ZnO

2012 ◽  
Vol 535-537 ◽  
pp. 214-218
Author(s):  
Qi Xin Wan ◽  
Jia Yi Chen ◽  
Zhi Hua Xiong ◽  
Dong Mei Li ◽  
Bi Lin Shao ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Formation Energy ◽  
Lattice Distortion ◽  
Theoretical Study ◽  
Functional Theory ◽  
Li Doping ◽  
The Density Functional Theory ◽  
Doped Zno ◽  
Good Agreement

The first-principles with pseudopotentials method based on the density functional theory was applied to calculate the geometric structure, the formation energy of impurities and the electronic structure of Li-doped ZnO. In the system of Li-doped ZnO, LiZn can not result in lattice distortion. In contrast with that case, LiO and Lii result in lattice distortion after Li doping in ZnO. In Li-doped ZnO, LiO is the most unstable than the other cases. Simultaneously, Lii is more stable than LiZn according to that Lii has smaller formation energy. Furthermore, the electronic structure of Li-doped ZnO indicates that that LiZn behaves as acceptor, while Lii behaves as donor. In conclusion, in Li-doped ZnO, Lii is always in the system to compensate the acceptor. Singly doping Li in ZnO is difficult to gain p-ZnO for the self-compensation. The results are in good agreement with other calculated and experimental results.

scholarly journals Thermoelectric characteristics of X$$_2$$YH$$_2$$ monolayers (X=Si, Ge; Y=P, As, Sb, Bi): a first-principles study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Ali Mohebpour ◽  
Shobair Mohammadi Mozvashi ◽  
Sahar Izadi Vishkayi ◽  
Meysam Bagheri Tagani
Keyword(s):  
Thermoelectric Materials ◽  
First Principles ◽  
Material Science ◽  
Figure Of Merit ◽  
Density Functional ◽  
Room Temperature ◽  
Boltzmann Transport Equation ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractEver since global warming emerged as a serious issue, the development of promising thermoelectric materials has been one of the main hot topics of material science. In this work, we provide an in-depth understanding of the thermoelectric properties of X$$_2$$ 2 YH$$_2$$ 2 monolayers (X=Si, Ge; Y=P, As, Sb, Bi) using the density functional theory combined with the Boltzmann transport equation. The results indicate that the monolayers have very low lattice thermal conductivities in the range of 0.09−0.27 Wm$$^{-1}$$ - 1 K$$^{-1}$$ - 1 at room temperature, which are correlated with the atomic masses of primitive cells. Ge$$_2$$ 2 PH$$_2$$ 2 and Si$$_2$$ 2 SbH$$_2$$ 2 possess the highest mobilities for hole (1894 cm$$^2$$ 2 V$$^{-1}$$ - 1 s$$^{-1}$$ - 1 ) and electron (1629 cm$$^2$$ 2 V$$^{-1}$$ - 1 s$$^{-1}$$ - 1 ), respectively. Si$$_2$$ 2 BiH$$_2$$ 2 shows the largest room-temperature figure of merit, $$ZT=2.85$$ Z T = 2.85 in the n-type doping ( $$\sim 3\times 10^{12}$$ ∼ 3 × 10 12  cm$$^{-2}$$ - 2 ), which is predicted to reach 3.49 at 800 K. Additionally, Si$$_2$$ 2 SbH$$_2$$ 2 and Si$$_2$$ 2 AsH$$_2$$ 2 are found to have considerable ZT values above 2 at room temperature. Our findings suggest that the mentioned monolayers are more efficient than the traditional thermoelectric materials such as Bi$$_2$$ 2 Te$$_3$$ 3 and stimulate experimental efforts for novel syntheses and applications.

scholarly journals Phase Stability in U-6Nb Alloy Doped with Ti from the First Principles Theory

2020 ◽  
Vol 10 (10) ◽  
pp. 3417
Author(s):  
Alexander Landa ◽  
Per Söderlind ◽  
Amanda Wu
Keyword(s):  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Room Temperature ◽  
Rapid Quenching ◽  
Quantum Mechanical ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Effect Of Impurities

First-principles calculations within the density-functional-theory (DFT) approach are conducted in order to explore and explain the effect of small amounts of titanium on phase stability in the U-6Nb alloy. During rapid quenching from high to room temperature, metastable phases α′ (orthorhombic), α″ (monoclinic), and γ0 (tetragonal) can form, depending on Nb concentration. Important mechanical properties depend on the crystal structure and, therefore, an understanding of the effect of impurities on phase stability is essential. Insights on this issue are obtained from quantum-mechanical DFT calculations. The DFT framework does not rely on any material-specific assumptions and is therefore ideal for an unbiased investigation of the U-Nb system.

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