INVESTIGATION OF STRUCTURAL PHASE TRANSFORMATION IN HALF METALLIC FERROMAGNETIC EuN UNDER PRESSURE

The results of first principles calculations of the electronic band structures, density of states, band gap, equilibrium lattice constants, cohesive energies, bulk moduli and magnetic moments are presented for the EuN with rock salt as ambient structure and cesium chloride as high-pressure structure. The tight-binding linear muffin tin orbital method within the local-density approximation is used. Both spin-polarized and non-spin polarized calculations are performed. The magnetic and structural stabilities are determined from the total energy calculations for both nonmagnetic (NM) and ferro-magnetic (FM) states. From the present study EuN illustrates half-metallic. The FM phase is more stable than NM phase. We further predict EuN undergoes a transition from NaCl -type (B1) to CsCl -type structure (B2) at 14.6 GPa, which could not be compared owing to the need of experimental and theoretical results. Futhermore, the bulk moduli, first-order pressure derivatives and magnetic moments are also estimated in B1 and B2 phases. The magnetic moment is estimated to be nearly 6 μB, which is in good agreement with the others reported value. A small decrease in magnetic moment is observed under pressure.

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AB INITIO ELECTRONIC STRUCTURE CALCULATIONS OF HALF-METALLIC FERROMAGNETISM IN CALCIUM CHALCOGENIDES DOPED WITH B, C AND N

Modern Physics Letters B ◽

10.1142/s0217984911026383 ◽

2011 ◽

Vol 25 (18) ◽

pp. 1537-1548 ◽

Cited By ~ 9

Author(s):

M. YOGESWARI ◽

G. KALAPANA

Keyword(s):

Ab Initio ◽

Magnetic Moment ◽

Local Density ◽

Magnetic Moments ◽

Electronic Band ◽

Half Metallic ◽

N Doping ◽

C And N ◽

Metallic Ferromagnetism ◽

Half Metallic Ferromagnetism

Self-consistent ab initio calculations were carried out to study the structural, electronic and magnetic properties of nine ternary compounds Ca 4 XA 3 ( X = B , C and N ; A = S , Se and Te ). The calculations were performed by using tight-binding linear muffin tin orbital (TB-LMTO) method within the local density approximation (LDA). The calculations reveal that half-metallic ferromagnetism can be obtained for C - and N -doping with the integer magnetic moment of 2.00 μ B and 1.00 μ B per cell. However, B substitution does not induce magnetism in CaS and CaSe systems, but it produces ferromagnetism in CaTe system with magnetic moment of 2.67 μ B per cell. Moreover C - and N -doping enhance the stable ferromagnetic state in calcium chalcogenide systems. Spin-dependent electronic band structure, total and partial densities of state calculations demonstrate that localized magnetic moments substantially come from impurity atoms. Half-metallic ferromagnetism predominately originates from spin-polarization of electrons in 2p orbital states of C and N atoms. In addition, equilibrium lattice constant, bulk modulus, atomic local magnetic moments, half-metallic gap and robustness of half-metallicity have been calculated.

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Ab initio Electronic Band Structure Calculations for Beryllium Chalcogenides

International Journal of Modern Physics B ◽

10.1142/s0217979298001149 ◽

1998 ◽

Vol 12 (19) ◽

pp. 1975-1984 ◽

Cited By ~ 43

Author(s):

G. Kalpana ◽

G. Pari ◽

A. Mookerjee ◽

A. K. Bhattacharyya

Keyword(s):

Bulk Modulus ◽

Band Gap ◽

Structural Transition ◽

Electronic Band Structure ◽

Local Density ◽

Structural Phase ◽

Experimental Results ◽

Orbital Method ◽

Electronic Band ◽

Indirect Band Gap

The first principles tight-binding linear muffin-tin orbital method within the local density approximation (LDA) has been used to calculate the ground state properties structural phase transition and pressure dependence of the band gap of BeS, BeSe and BeTe. We have calculated the energy-volume relations for these compounds in the B3 and B8 phases. The calculated lattice parameters, bulk modulus and the pressure-volume relation were found to be in good agreement with the recent experimental results. We have also calculated the cohesive energy for them and they are consistent with the bulk modulus. The calculated B3 to B8 structural transition pressure for BeS, BeS and BeTe agree well with the experimental results. Our calculations show that these compounds are indirect band gap (Γ-X) semiconductors at ambient conditions. The calculated band gap values are found to be underestimated by 20–30% which is due to the usage of LDA. After the structural transition to the B8 phase BeS continues to be indirect band gap semiconductor and ultimately it becomes metallic above 100 GPa. BeSe and BeTe are metallic at B3 to B8 structural transition.

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Ab Initio Study of Pressure-Induced Structural Properties of Uranium Chalcogenides

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1047.155 ◽

2014 ◽

Vol 1047 ◽

pp. 155-161

Author(s):

Archana Singh ◽

Mahendra Aynyas ◽

S.P. Sanyal

Keyword(s):

Phase Transition ◽

Structural Phase Transition ◽

Phase Structure ◽

Structural Phase ◽

Tight Binding ◽

First Principles Calculation ◽

Orbital Method ◽

Cscl Type ◽

Spin Polarized ◽

Total Energies

We report a first principles calculation of pressure-induced structural phase transition properties of uranium chalcogenides (UX; X=S, Se and Te). The total energies as a function of volume are obtained by means of self-consistent tight binding linear muffin orbital method (TB-LMTO) by performing spin and non-spin polarized calculations to determine the magnetic and structural stabilities. From the present study, we predict a magnetic phase transition from ferromagnetic (FM) to non-magnetic (NM) state around 67.7 and 10.2 GPa for US and USe, respectively. The pressure-induced magnetic transitions are found second-order in nature. We have also predicted structural phase transition from FM-NaCl-type (B1phase) structure to NM-CsCl-type (B2phase) structure at around 77.5, 23.5 for US and USe, respectively, while UTe undergoes from FM-B1to FM-B2phase around 12.0 GPa.

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Electronic and structural properties of rare earth pnictides

Materials Science-Poland ◽

10.1515/msp-2016-0026 ◽

2016 ◽

Vol 34 (1) ◽

pp. 45-52 ◽

Cited By ~ 2

Author(s):

Ramakant Bhardwaj

Keyword(s):

Rare Earth ◽

Electronic Band Structure ◽

Local Density ◽

Structural Parameters ◽

Structural Phase ◽

Tight Binding ◽

Lattice Parameter ◽

Type Structure ◽

Present Calculation ◽

Electronic Band

AbstractIn the present paper structural and electronic properties of rare earth pnictides have been presented. The present calculation has been performed using self-consistent tight binding linear muffin tin orbital (TB-LMTO) method within the local density approximation (LDA). The studied compounds undergo a structural phase transition from NaCl-type structure to CsCl-type structure. The electronic band structure and density of states of the pnictides have been reported. The equilibrium lattice parameter a (Å), bulk modulus B (GPa), number of f-states at the Fermi level Nf (states/Ry cell) and volume collapse of AmBi and CmBi have also been reported. The calculated equilibrium structural parameters are in good agreement with the available experimental results.

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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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Spin Gapless Semiconductor–Nonmagnetic Semiconductor Transitions in Fe-Doped Ti2CoSi: First-Principle Calculations

Applied Sciences ◽

10.3390/app8112200 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2200 ◽

Cited By ~ 3

Author(s):

Yu Feng ◽

Zhou Cui ◽

Ming-sheng Wei ◽

Bo Wu ◽

Sikander Azam

Keyword(s):

Magnetic Moment ◽

Electronic Structures ◽

Magnetic Moments ◽

Total Magnetic Moment ◽

First Principle ◽

Half Metallic ◽

Heusler Compound ◽

First Principle Calculations ◽

Metallic Ferromagnet

Employing first-principle calculations, we investigated the influence of the impurity, Fe atom, on magnetism and electronic structures of Heusler compound Ti2CoSi, which is a spin gapless semiconductor (SGS). When the impurity, Fe atom, intervened, Ti2CoSi lost its SGS property. As TiA atoms (which locate at (0, 0, 0) site) are completely occupied by Fe, the compound converts to half-metallic ferromagnet (HMF) TiFeCoSi. During this SGS→HMF transition, the total magnetic moment linearly decreases as Fe concentration increases, following the Slate–Pauling rule well. When all Co atoms are substituted by Fe, the compound converts to nonmagnetic semiconductor Fe2TiSi. During this HMF→nonmagnetic semiconductor transition, when Fe concentration y ranges from y = 0.125 to y = 0.625, the magnetic moment of Fe atom is positive and linearly decreases, while those of impurity Fe and TiB (which locate at (0.25, 0.25, 0.25) site) are negative and linearly increase. When the impurity Fe concentration reaches up to y = 1, the magnetic moments of Ti, Fe, and Si return to zero, and the compound is a nonmagnetic semiconductor.

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Electronic structure, Mechanical and Thermodynamic properties of CoYSb (Y= Cr, Mo, W) half-Heusler compounds as potential spintronic materials

10.21203/rs.3.rs-1033376/v1 ◽

2021 ◽

Author(s):

O. T. Uto ◽

J. O. Akinlami ◽

S. Kenmoe ◽

G. A. Adebayo

Keyword(s):

Density Functional ◽

Electronic Band Structure ◽

Structural Phase ◽

Covalent Bond ◽

Stable Phase ◽

Type I ◽

Generalized Gradient ◽

Electronic Density ◽

Electronic Band ◽

Half Metallic

Abstract The CoYSb (Y = Cr, Mo and W) compounds which are XYZ type half-Heusler alloys and also exist in the face centred cubic MgAgAs-type struc-ture conform to F ̄43m space group. In the present work, these compoundsare investigated in different atomic arrangements called, Type-I, Type-II andType-III phases, using Generalized Gradient Approximation (GGA) in the Density Functional Theory (DFT) implemented in QE (Quantum EspressoAb-Initio Simulation Package). The ferromagnetic state of these alloys is studied after investigating their stable structural phase. The calculated electronic band structure and the total electronic density of states indicated nearly half-metallic behaviour in CoMoSb with a possibility of being used in spintronic application, metallic in CoWSb and half-metallic in CoCrSb, with the minority spin band gap of 0.81 eV. Furthermore, the calculated mechanical properties predicted an anisotropic behaviour of these alloys in the stable phase. Finally, due to its high Debye temperature value, CoCrSb possesses a stronger covalent bond than CoMoSb and CoWSb, respectively.

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Ab-Initio Study of the Electronic and Magnetic Properties of Boron- and Nitrogen-Doped Penta-Graphene

Nanomaterials ◽

10.3390/nano10040816 ◽

2020 ◽

Vol 10 (4) ◽

pp. 816 ◽

Cited By ~ 1

Author(s):

Chao Zhang ◽

Yu Cao ◽

Xing Dai ◽

Xian-Yong Ding ◽

Leilei Chen ◽

...

Keyword(s):

Magnetic Properties ◽

Charge Transfer ◽

First Principles ◽

Magnetic Moments ◽

First Principles Calculations ◽

Electronic Band ◽

Magnetic Devices ◽

Spin Polarized ◽

Electronic Band Gap ◽

Transfer Mechanisms

First-principles calculations were performed to investigate the effects of boron/nitrogen dopant on the geometry, electronic structure and magnetic properties of the penta-graphene system. It was found that the electronic band gap of penta-graphene could be tuned and varied between 1.88 and 2.12 eV depending on the type and location of the substitution. Moreover, the introduction of dopant could cause spin polarization and lead to the emergence of local magnetic moments. The main origin of the magnetic moment was analyzed and discussed by the examination of the spin-polarized charge density. Furthermore, the direction of charge transfer between the dopant and host atoms could be attributed to the competition between the charge polarization and the atomic electronegativity. Two charge-transfer mechanisms worked together to determine which atoms obtained electrons. These results provide the possibility of modifying penta-graphene by doping, making it suitable for future applications in the field of optoelectronic and magnetic devices.

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Electronic band structure of silver low-index surfaces: a tight-binding study

Canadian Journal of Physics ◽

10.1139/cjp-2019-0218 ◽

2020 ◽

Vol 98 (5) ◽

pp. 488-496

Author(s):

H.J. Herrera-Suárez ◽

A. Rubio-Ponce ◽

D. Olguín

Keyword(s):

Band Structure ◽

Density Of States ◽

Electronic Band Structure ◽

Local Density ◽

Tight Binding ◽

Theoretical Data ◽

Binding Study ◽

Local Density Of States ◽

Electronic Band ◽

Tight Binding Method

We studied the electronic band structure and corresponding local density of states of low-index fcc Ag surfaces (100), (110), and (111) by using the empirical tight-binding method in the framework of the Surface Green’s Function Matching formalism. The energy values for different surface and resonance states are reported and a comparison with the available experimental and theoretical data is also done.

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Half-metallic properties in Co2XSn (X = Ti, V and Cr) full-Heusler compound

Modern Physics Letters B ◽

10.1142/s0217984920500281 ◽

2019 ◽

Vol 34 (02) ◽

pp. 2050028 ◽

Cited By ~ 4

Author(s):

H. Abbassa ◽

A. Labdelli ◽

S. Meskine ◽

Y. Benaissa Cherif ◽

A. Boukortt

Keyword(s):

Magnetic Moment ◽

Density Functional ◽

Heusler Alloys ◽

Electronic Band ◽

Half Metallic ◽

Lattice Constants ◽

Half Metal ◽

Wide Range ◽

Metallic Ferromagnetism ◽

Half Metallic Ferromagnetism

First-principles calculations based on density functional theory (DFT) confirm the half-metallic ferromagnetism in both [Formula: see text] and [Formula: see text], and the nearly half-metallic ferromagnetism in [Formula: see text] Heusler alloys with the [Formula: see text]-type structure [Formula: see text]. The electronic band structures and density of states (DOS) calculations of the [Formula: see text] and [Formula: see text] compounds show that the spin-up electrons are metallic, whereas the spin-down bands are semiconducting with a gap of 0.47 eV and 0.53 eV, respectively, with 0.21 eV and 0.36 eV as a spin-flip gap, respectively. The [Formula: see text] and [Formula: see text] Heusler were half-metal compounds with magnetic moment of [Formula: see text] and [Formula: see text] at the equilibrium lattice constants [Formula: see text] Å and [Formula: see text] Å, respectively, which agrees with the Slater–Pauling rule, and have 100% polarization for a wide range of lattice parameters. The [Formula: see text] is a nearly half-metal (NHF) compound with magnetic moment of [Formula: see text] and 92.9% polarization at the equilibrium lattice constants [Formula: see text] Å and acquire half-metal behavior under the pressure 16.70 GPa.

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