Electronic structure and magnetization of Zn1-xCoxO ternary alloys with zinc-blende, rocksalt and wurtzite phases

Abstract First-principles all electrons density-functional calculations for the band structure and magnetization of Zn1 − xCoxO ternary magnetic alloys, in three phases namely zinc-blende, rocksalt and wurtzite have been reported. The computations are spin-polarized. An inspection of our electronic properties showed that the alloy system of interest exhibits a semiconducting character where the nature of the gap depends on the considered phase. An analysis of electronic charge density suggests that the bonding has a partially covalent character for ZnO which becomes weaker as far as the Co concentration increases. CoO is found to reach a total magnetization of 3 µB per cell for zinc-blende and rocksalt phases and 6 µB per cell for wurtzite phase.

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FERROMAGNETIC PROPERTIES IN V-DOPED AlN FROM FIRST PRINCIPLES

Modern Physics Letters B ◽

10.1142/s0217984912501321 ◽

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.

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Influence of Electric Field in the Adsorption of Atomic Hydrogen on Graphene

Advances in Condensed Matter Physics ◽

10.1155/2015/847804 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

C. Cab ◽

R. Medina-Esquivel ◽

C. Acosta ◽

J. Mendez-Gamboa ◽

F. Peñuñuri ◽

...

Keyword(s):

Electric Field ◽

Charge Density ◽

Electric Fields ◽

Atomic Hydrogen ◽

Density Functional ◽

Electronic Charge ◽

Generalized Gradient ◽

Electronic Charge Density ◽

System A ◽

Spin Polarized

The influence of external electric field (EF) in the adsorption of atomic hydrogen on graphene (H/G) was studied by means of electronic structure calculations based on spin-polarized density functional theory with generalized gradient approximation (GGA). The changes in atomic hydrogen physisorption-chemisorption on graphene owed to EF (which ranged between −1.25 V/Å and 0.75 V/Å) were determined. Analysis of the electronic charge density for an H/G system explained the EF influences on the adsorption properties (analyzing changes in electronic charge density for H/G system). A decrease of more than 100% in the chemisorption barrier for an EF of −1.25 V/Å was found. The changes in the electronic charge density confirm the possibility of manipulating the physical-chemical adsorption of hydrogen on graphene by applying electric fields.

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Magnetic Properties of Embedded Rh Clusters in Ni Matrix

MRS Proceedings ◽

10.1557/proc-384-535 ◽

1995 ◽

Vol 384 ◽

Author(s):

Zhi-Qiang Li ◽

Yuichi Hashi ◽

Jing-Zhi Yu ◽

Kaoru Ohno ◽

Yoshiyuki Kawazoe

Keyword(s):

Magnetic Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Magnetic Moments ◽

Functional Formalism ◽

Rhodium Clusters ◽

Spin Polarized ◽

Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

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FIRST PRINCIPLES DENSITY FUNCTIONAL INVESTIGATION OF SUPPORTED TUNGSTEN CLUSTER (Wn; n = 1 TO 6) ON ANCHORED GRAPHITE (0001) SURFACE

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684113500152 ◽

2013 ◽

Vol 02 (03n04) ◽

pp. 1350015

Author(s):

SONALI BARMAN ◽

G. P. DAS ◽

Y. KAWAZOE

Keyword(s):

First Principles ◽

Density Functional ◽

Metal Clusters ◽

Theoretical Study ◽

First Principles Calculations ◽

Novel Technique ◽

Defect Site ◽

Positive Ions ◽

Spin Polarized ◽

Functional Investigation

Size-selected Wn clusters can be deposited firmly on a graphite (0001) surface using a novel technique, where the positive ions (of the same metal atom species) embedded on the graphite surface by ion implantation, act as anchors. The size selected metal clusters can then soft land on this anchored surface m [Hayakawa et al., 2009]. We have carried out a systematic theoretical study of the adsorption of Wn (n = 1-6) clusters on anchored graphite (0001) surface, using state-of-art spin-polarized density functional approach. In our first-principles calculations, the graphite (0001) surface has been suitably modeled as a slab separated by large vacuum layers. Wn clusters bond on clean graphite (0001) surface with a rather weak Van-der-Waals interaction. However, on the anchored graphite (0001) surface, the Wn clusters get absorbed at the defect site with a much larger adsorption energy. We report here the results of our first-principles investigation of this supported Wn cluster system, along with their reactivity trend as a function of the cluster size (n).

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.378 ◽

2014 ◽

Vol 887-888 ◽

pp. 378-383 ◽

Cited By ~ 2

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.

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First-principles investigation of the electronic band structures and optical properties of quaternary ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) metal chalcogenides

International Journal of Modern Physics B ◽

10.1142/s021797921850337x ◽

2018 ◽

Vol 32 (30) ◽

pp. 1850337

Author(s):

Shahid Ullah ◽

Hayat Ullah ◽

Abdullah Yar ◽

Sikander Azam ◽

A. Laref

Keyword(s):

Optical Properties ◽

First Principles ◽

Density Functional ◽

Correlation Energy ◽

Electronic Charge ◽

Electromagnetic Spectrum ◽

Metal Chalcogenides ◽

Electronic Band ◽

Charge Densities ◽

Electronic Band Structures

In this paper, we study the optoelectronic properties of quaternary metal chalcogenide semiconductor ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) compounds using state-of-the-art density functional theory (DFT) with TB-mBJ approximation for the treatment of exchange-correlation energy. In particular, the electronic and optical properties of the relaxed geometries of these compounds are investigated. Our first-principles ab-initio calculations show that the CsBaPS4 and RbBaPS4 compounds have direct bandgaps whereas the CsBaVS4 compound exhibits indirect bandgap nature. Importantly, the theoretically calculated values of the bandgaps of the compounds are consistent with experiment. Furthermore, our analysis of the electronic charge densities of these compounds indicates that the above quaternary chalcogenides have mixed covalent and ionic bonding characters. The effective masses of these compounds are also calculated which provide very useful information about the band structure and transport characteristics of the investigated compounds. Similarly, high absorptivity in the visible and ultraviolet regions of the electromagnetic spectrum possibly predicts and indicates the importance of these materials for potential optoelectronic applications in this range.

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Electronic and optical properties of zinc-blende GeC by first principles study

Modern Physics Letters B ◽

10.1142/s0217984915501031 ◽

2015 ◽

Vol 29 (20) ◽

pp. 1550103

Author(s):

Jinhui Zhai ◽

Jinguang Zhai ◽

Ajun Wan

Keyword(s):

Optical Properties ◽

First Principles ◽

Density Functional ◽

Dielectric Constants ◽

Electronic And Optical Properties ◽

Optical Functions ◽

Zinc Blende ◽

The Density Functional Theory ◽

Valence Bands ◽

Energy Dependent

The electronic and optical properties of zinc-blende (zb)[Formula: see text]GeC have been investigated using first principles calculations based on the density functional theory (DFT). The obtained band gap of zb–GeC is 2.30[Formula: see text]eV by means of Heyd–Scuseria–Ernzerhof (HSE) functional. We have discussed the energy-dependent optical functions including dielectric constants, refractive index, absorption, reflectivity, and energy-loss spectrum in detail. The results reveal that zb–GeC has a higher static dielectric constant compared with that of zb–SiC. The optical functions are mainly associated with the interband transitions from the occupied valence bands (VBs) Ge[Formula: see text][Formula: see text] and C[Formula: see text][Formula: see text] states to Ge[Formula: see text][Formula: see text], [Formula: see text] and C[Formula: see text][Formula: see text] states of the unoccupied conduction bands (CBs).

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Density functional calculations of elastic and thermal properties of zinc-blende HgSxSe1−x, HgSxTe1−x and HgSexTe1−x ternary alloys

Computational Condensed Matter ◽

10.1016/j.cocom.2020.e00482 ◽

2020 ◽

Vol 24 ◽

pp. e00482

Author(s):

Manish Debbarma ◽

Subhendu Das ◽

Bimal Debnath ◽

Debankita Ghosh ◽

Sayantika Chanda ◽

...

Keyword(s):

Thermal Properties ◽

Density Functional Calculations ◽

Density Functional ◽

Ternary Alloys ◽

Zinc Blende

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First-principles investigation of the structural, elastic, electronic, and optical properties of semiconducting AgBr1–xIx (0 ≤ x ≤ 1) ternary alloys in rock-salt and zinc blende structures

Canadian Journal of Physics ◽

10.1139/cjp-2019-0357 ◽

2020 ◽

Vol 98 (9) ◽

pp. 834-848

Author(s):

H. Rekab-Djabri ◽

Mohamed Drief ◽

Manal M. Abdus Salam ◽

Salah Daoud ◽

F. El Haj Hassan ◽

...

Keyword(s):

Optical Properties ◽

Band Gap ◽

Rock Salt ◽

Density Functional ◽

Local Density ◽

Ternary Alloys ◽

Full Potential ◽

Zinc Blende ◽

Lmto Method ◽

Direct Band

In this work, first principle calculations of the structural, electronic, elastic, and optical properties of novel AgBr1–xIx ternary alloys in rock-salt (B1) and zinc-blende (B3) structures are presented. The calculations were performed using the full-potential linear muffin-tin orbital (FP-LMTO) method within the framework of the density functional theory (DFT). The exchange and correlation potentials were treated according to the local density approximation (LDA). The lattice constants for the B1 and B3 phases versus iodide concentration (x) were found to deviate slightly from the linear relationship of Vegard’s law. The calculated electronic properties showed that AgBr1–xIx alloys in the B3 structure have a direct band gap (Γ – Γ) for all concentrations of x, which means that they can be used in long-wavelength optoelectronic applications, while in the B1 structure they have an indirect (Γ – R) band gap. The elastic constants Cij, shear modulus G, Young’s modulus E, Poisson’s ratio ν, index of ductility B/G, sound velocities vt, vl, and vm, and Debye temperature θD were also reported and analyzed. By incorporating the basic optical properties, we discussed the dielectric function, refractive index, optical reflectivity, absorption coefficient, and optical conductivity in terms of incident photon energy up to 13.5 eV. The present results were found to be in good agreement with the available experimental and other theoretical results.

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First-Principles Study of Molecular Adsorption of Hydrogen/s on Co-Adatom Graphene

Journal of Institute of Science and Technology ◽

10.3126/jist.v25i1.29418 ◽

2020 ◽

Vol 25 (1) ◽

pp. 15-23

Author(s):

Nurapati Pantha ◽

Saroj Thapa ◽

Narayan Prasad Adhikari

Keyword(s):

Magnetic Properties ◽

Binding Energy ◽

First Principles ◽

Molecular Hydrogen ◽

Density Functional ◽

Hydrogen Molecule ◽

Cobalt Atom ◽

Electronic Charge ◽

Practical Applications ◽

Electronic And Magnetic Properties

The study of graphene and its allotropes help to understand fundamental science and their role in the industry. The adsorption of transition metal adatom on mono-layer graphene can tune the geometrical, electronic, and magnetic properties of the material according to the requirement for the practical applications. In the present work, the geometrical stability, electronic and magnetic properties, and also the redistribution of electronic charge of single cobalt atom (Co) adsorbed graphene with reference to pure graphene have been investigated to develop a model system for the effective storage of hydrogen. The density functional theory (DFT) based first-principles calculations by incorporating van der Waals (VDW) interactions within DFT-D2 levels of approximation implemented in the quantum ESPRESSO package was used. The band structure and density of states of cobalt-adatom graphene show that the material is metallic and magnetic with a total magnetic moment of 1.55 μB. The change in the electronic distribution of Co-adatom graphene has been found favorable for adsorbing molecular hydrogen/s with greater strength. The increasing number of adsorbed molecular hydrogen/s (n=1 to 7) onto the substrate shows varying binding energy per hydrogen molecule, high enough at low concentration (n=1, 2, and 3), and then decreases slowly on increasing the value of n. The nature of adsorption and binding energy per hydrogen molecule (with a range of 0.116 - 0.731 eV/ H2) are found useful to meet a standard target for hydrogen storage in such materials.

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