scholarly journals First-Principles Study of Electronic and Magnetic Properties of Anatase and its Role in Anatase-Mxene Nanocomposite

2019 ◽  
Vol 5 (1) ◽  
pp. 42-53
Author(s):  
D. Parajuli ◽  
G. C. Kaphle ◽  
K. Samatha
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Charge Density ◽  
Density Of States ◽  
Density Functional ◽  
Tight Binding ◽  
Total Density ◽  
Energy Storage Devices ◽  
Orbital Contribution ◽  
Electronic And Magnetic Properties

The electronic and magnetic properties of Titanium and one of its oxide Anatase are calculated by using Tight Binding Linear Muffin-Tin Orbital Atomic Sphere Approximation (TB-LMTO-ASA) method under Density Functional Theory (DFT). The lattice parameter, band structure, Density of States (DOS) and charge density distributions of Ti and TiO2 (Anatase) required for electronic structure are calculated respectively. The orbital contribution is analyzed by fat band structure; the d- orbital on conduction band and, s and p orbitals on valance bands. Consequently, their magnetic properties are checked. From our study, we found that the magnetic moments of Ti and TiO2 are found to be 2.2 μB and 0 respectively. The total Density of States for spin up and down electron have smaller difference in Ti and symmetric in TiO2 indicates that Ti slightly paramagnetic and Anatase is non magnetic in nature. The charge density plots reveals the concentration of electrons at the site under study. Anatase can be deposited onto Mxene to form Mxene-Anatase nanocomposite which has several excellent applications in the field of biosensors, biocompatible materials, energy storage devices, topological insulators etc.

scholarly journals First-principles study of structural, electronic and magnetic properties of Co-based quaternary Heusler compounds: CoFeCrAl, CoFeTiAs, CoFeCrGa and CoMnVAs

BIBECHANA ◽  
2017 ◽  
Vol 15 ◽  
pp. 50-59 ◽  
Author(s):  
Bikram Pandey ◽  
Ram Babu Ray ◽  
Gopi Chandra Kaphle
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Total Density ◽  
Heusler Compounds ◽  
Electronic Band ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

We study the Structural, Electronic and Magnetic properties of Co-based LiMgPdSn-types of quaternary Heusler compounds (CoFeCrAl, CoFeTiAs, CoFeCrGa, and CoMnVAS) using Density Functional Theory (DFT) implemented on Tight Binding Linear Muffin-Tin Orbital within Atomic Sphere Approximation(TB-LMTO-ASA) Code. The optimized value of lattice parameter for CoFeCrAl, CoFeTiAs, CoFeCrGa and CoMnVAs are found to be 5.61A˚, 5.76 A˚, 5.61A˚ and 5.71A˚ respectively. From the calculation of electronic band structure and spin polarized total density of states (DOS), we found that CoFeCrAl and CoFeCrGa are spin-gapless semiconductor with half-metallic gap of 0.82eV and 0.25eV respectively. CoFeTiAs half-metals (Nearly spin-gapless semiconductor) with half-metallic gap 0.38 eV and CoMnVAs is found to be nearly gapless half-metal. Magnetic moment of these compounds almost obey the Slater-Pauling rules. All these compounds  expected to have high curie temperature which makes them significant for spintroincs/magnetoelectroincs applications.BIBECHANA 15 (2018) 50-59 

scholarly journals Electronic and Magnetic Properties of Half Metallic Heusler Alloy Co2MnSi: A First-Principles Study

2017 ◽  
Vol 4 (1) ◽  
pp. 60
Author(s):  
Prakash Sharma ◽  
Gopi Chandra Kaphle
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Heusler Alloy ◽  
Density Functional ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

<p class="Default">Heusler alloys have been of great interest because of their application in the field of modern technological applications. Electronic and magnetic properties of Co, Mn, Si and the Heusler alloy Co<sub>2</sub>MnSi have been studied using Density functional theory based Tight Binding Linear Muffin Tin Orbital with Atomic Sphere Approximation (TB-LMTO-ASA) approach. From the calculation lattice parameter of optimized structure of Co, Mn, Si and Co<sub>2</sub>MnSi are found to be 2.52Å, 3.49Å, 5.50Å, 5.53Å respectively. Band structure calculations show that Co and Mn are metallic, Si as semi-conducting while the Heusler alloy Co<sub>2</sub>MnSi as half-metallic in nature with band gap 0.29eV. The charge density plot indicates major bonds in Co<sub>2</sub>MnSi are ionic in nature. Magnetic property has been studied using the density of states (DOS), indicating that Co and Co2MnSi are magnetic with magnetic moments 2.85μ<sub>B</sub> and 4.91μ<sub>B</sub> respectively. The contribution of orbital in band structure, DOS and magnetic moments are due to d-orbital of Co and Mn and little from s and p-orbital of Si in Co<sub>2</sub>MnSi alloy.</p><p><strong>Journal of Nepal Physical Society</strong><em><br /></em>Volume 4, Issue 1, February 2017, Page: 60-66</p>

scholarly journals Structural, Electronic and Magnetic Properties of Defected Water Adsorbed Single-Layer MoS2

2021 ◽  
Vol 26 (1) ◽  
pp. 43-50
Author(s):  
Hari Krishna Neupane ◽  
Narayan Prasad Adhikari
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Density Of States ◽  
Density Functional ◽  
Single Layer ◽  
Vacancy Defect ◽  
Partial Density ◽  
Energy Bands ◽  
Vacancy Defects ◽  
Electronic And Magnetic Properties

Water adsorbed in MoS2 (wad-MoS2), 1S atom vacancy defect in wad-MoS2 (1S-wad-MoS2), 2S atoms vacancy defects in wad-MoS2 (2S-wad-MoS2), and 1Mo atom vacancy defect in wad-MoS2 (Mo-wad-MoS2) materials were constructed, and their structural, electronic, and magnetic properties were studied by spin-polarized density functional theory (DFT) based first-principles calculations. The wad-MoS2, 1S-wad-MoS2, 2S-wad-MoS2, and Mo-wad-MoS2 materials were found stable. From band structure calculations, wad-MoS2, 1S-wad-MoS2 and 2S-wad-MoS2 materials open energy bandgap of values 1.19 eV, 0.65 eV and 0.38 eV respectively. Also, it was found that the conductivity strength of the material increases with an increase in the concentration of S atom vacancy defects in the structure. On the other hand, the Mo-wad-MoS2 material has metallic properties because energy bands of electrons crossed the Fermi energy level in the band structure. For the investigation of magnetic properties, the density of states (DoS) and partial density of states (PDoS) calculations were used and found that wad-MoS2, 1S-wad-MoS2, and 2S-wad-MoS2 are non-magnetic materials, while Mo-wad-MoS2 is a magnetic material. The total magnetic moment of Mo-wad-MoS2 has a value of 2.66 µB/cell, due to the arrangement of unpaired up-spin and down-spin of electrons in 3s & 3p orbitals of S atoms; and 4p, 4d & 5s orbitals of Mo atoms in the material.

Electronic and Magnetic Properties of Half Metallic Heusler Alloy Co2mnsi: A First-Principles Study

2017 ◽  
pp. 31-36
Author(s):  
Prakash Sharma ◽  
Gopi Chandra Kaphle
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Heusler Alloy ◽  
Density Functional ◽  
Heusler Alloys ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
Sphere Approximation

Heusler alloys have been of great interest because of their application in the field of modern technological word. Electronic and magnetic properties of Co, Mn, Si and the Heusler alloy Co2MnSi have been studied using Density functional theory based Tight Binding Linear Muffin Tin Orbital with Atomic Sphere Approximation (TB-LMTO-ASA) approach. From the calculation lattice parameter of optimized structure of Co, Mn, Si and Co2MnSi are found to be 2.52A0 , 3.49A0 , 5.50A0 , 5.53A0 respectively. Band structure calculations show that Co and Mn are metallic, Si as semi-conducting while the Heusler alloy Co2MnSi as half-metallic in nature with band gap 0.29eV. The charge density plot indicates major bonds in Co2MnSi are ionic in nature. Magnetic property has been studied using the density of states (DOS), indicating that Co and Co2MnSi are magnetic with magnetic moment 2.85μB and 4.91μB respectively. The contribution of orbitals in band, DOS and magnetic moment are due to d-orbitals of Co and Mn and little from s and p-orbital of Si in Co2MnSi.The Himalayan Physics Vol. 6 & 7, April 2017 (31-36)

scholarly journals Electronic band structure, optical, dynamical and thermodynamic properties of cesium chloride (CsCl) from first-principles

2015 ◽  
Vol 6 ◽  
pp. A7 ◽  
Author(s):  
Suat Bingol ◽  
Bahattin Erdinc ◽  
Harun Akkus
Keyword(s):  
Thermodynamic Properties ◽  
Band Structure ◽  
Density Of States ◽  
Ground State ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Cesium Chloride ◽  
Total Density ◽  
Electronic Band ◽  
Ground State Properties

The geometric structural optimization, electronic band structure, total density of states for valence electrons, density of states for phonons, optical, dynamical, and thermodynamical features of cesium chloride have been investigated by linearized augmented plane wave method using the density functional theory under the generalized gradient approximation. Ground state properties of cesium chloride are studied. The calculated ground state properties are consistent with experimental results. Calculated band structure indicates that the cesium chloride structure has an indirect band gap value of 5.46 eV and is an insulator. From the obtained phonon spectra, the cesium chloride structure is dynamically stable along the various directions in the Brillouin zone. Temperature dependent thermodynamic properties are studied using the harmonic approximation model.

scholarly journals Tight-binding dispersion of the prismatic pentagonal lattice

2018 ◽  
Vol 32 (01) ◽  
pp. 1750273
Author(s):  
Susobhan Paul ◽  
Asim Kumar Ghosh
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Parameter Space ◽  
Tight Binding ◽  
Dispersion Relations ◽  
Total Density ◽  
Zero Energy ◽  
Dirac Cone ◽  
Analytic Expressions ◽  
Total Density Of States

Tight-binding Hamiltonian on the prismatic pentagonal lattice is exactly solved to obtain the analytic expressions of dispersion relations and eigenvectors. This lattice is made of prismatic pentagon which is different from Cairo pentagon. Six different dispersion relations and total density of states are obtained. Dispersion relations are symmetric about the zero energy at a particular point in the parameter space. Although a large gap is found for the Cairo pentagonal lattice, no gap as well as no Dirac cone is found to appear in the tight-binding band structure for this prismatic pentagonal lattice. Instead, a pair of van Hove singularities has been identified at two different energy values in the band structure.

Adsorption-site dependence of electronic and magnetic properties of hydrogen impurities on bilayer graphene

2015 ◽  
Vol 29 (28) ◽  
pp. 1550198
Author(s):  
Mahboobeh Mirzadeh ◽  
Mani Farjam
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Bilayer Graphene ◽  
Binding Model ◽  
Electronic And Magnetic Properties ◽  
A Site ◽  
Site Dependence

In bilayer graphene, the A and B sites in each layer have different local electronic structures due to the presence of the second layer. In this work, using first-principles calculations, we examine the effect of sublattice inequivalence on various properties of hydrogen defects in bilayer graphene. Density functional calculations show that induced magnetic moments by H adsorption on A and B sites of bilayer graphene are both equal to [Formula: see text] at zero temperature, but change slightly and develop a mismatch at finite temperature. We show how this variation follows from the fact that H on A site remains gapless but H on B site opens an energy gap. We also use a tight-binding model to explain the differences in band structures for H adsorption on A and B sites. The results obtained in this work suggest that there are important differences in electronic and magnetic properties between H adsorption on monolayer and bilayer graphene.

scholarly journals Structural, electronic and magnetic properties of Fe, Co, Ni monatomic nanochains encapsulated in armchair LiF nanotubes

2017 ◽  
Vol 35 (2) ◽  
pp. 283-290
Author(s):  
B. Arghavani Nia ◽  
R. Moradian ◽  
M. Shahrokhi
Keyword(s):  
Magnetic Properties ◽  
Spin Polarization ◽  
Magnetic Moment ◽  
Density Functional ◽  
Magnetic Nanostructures ◽  
Spin Splitting ◽  
Total Density ◽  
Generalized Gradient ◽  
Electronic And Magnetic Properties ◽  
Atomic Chains

Abstract Structural, electronic and magnetic properties of transition metal TM (TM = Fe, Co and Ni) atomic chains wrapped in single walled LiF armchair nanotubes have been investigated by the first-principles calculations in the framework of the density functional theory. The generalized gradient approximation (GGA) with Hubbard repulsion potential and without Hubbard repulsion was employed to describe the exchange-correlation potential. It is found that all these TM chains @LiFNTs systems have negative formation energy so they are stable and exothermic. Total density of states and partial densities of states analyses show that the spin polarization and the magnetic moment of TM chains @LiFNTs(n,n) systems come mostly from the TM atom chains. All these nanocomposites are ferromagnetic (FM) and spin splitting between spin up and down is observed. The high magnetic moment and spin polarization of the TM chains @LiFNT(n,n) systems show that they can be used as magnetic nanostructures possessing potential current and future applications in permanent magnetism, magnetic recording, and spintronics.

scholarly journals Dynamic, Electronic and Optical Properties of Fm3m-HgF2: A DFT Approach

2021 ◽  
Author(s):  
M VAGHELA ◽  
Dhara Raval ◽  
Bindiya Babariya ◽  
P.N. Gajjar
Keyword(s):  
Band Structure ◽  
Charge Density ◽  
Density Of States ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Electronic Band Structure ◽  
Random Phase ◽  
Visible Region ◽  
Optical Parameters ◽  
Electronic Band

In the present work, the cubic structure of HgF2 has been studied using generalized gradient approximation within the framework of density functional theory. Here, the positive phonon frequencies in the phonon dispersion curves show stability of the structure. The elastic constants also satisfy criteria of being kinetically stable material. The B/GH ratio 2.56 of HgF2 indicates its ductile nature. The thermodynamic intrinsic parameters of HgF2 have been calculated using linear response method where the temperature variations of Helmholtz free energy (F), internal energy (E), specific heat at constant volume (Cv) and Debay temperature (ϴD) have been studied. The explanation of the bonding nature is discussed using electronic band structure, density of states and charge density. Here, the presence of the wide valence band gap in electronic band structure and density of states displays the ionic behaviors of HgF2. In addition, the charge density along the [111] plane defines hybridization in between ‘s’, ‘p’ and ‘d’ orbitals in HgF2. The optical parameters of Fm3m-HgF2 were calculated using Random Phase Approximation. Here, the found static refractive index is 1.26. The general optical study showing the trend of being transparent in most of the UV region and fully transparent in the visible region by ionic Fm3m HgF2. Also, it shows significant absorption in the entire UV region and a long absorption tail which extends into the visible region.

scholarly journals Effect of (0001) Strain on the Electronic and Magnetic Properties of the Half-Metallic Ferromagnet Fe2Si

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Wang Chen ◽  
Ruijie Li ◽  
Yanhui Liu
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Fermi Surface ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
Metallic Ferromagnet ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

The electronic and magnetic properties of the half-metallic ferromagnet Fe2Si under (0001) strain have been evaluated by the first-principles density functional theory method. The spin-up band structure shows that bulk Fe2Si has metallic character, whereas the spin-down band structure shows that bulk Fe2Si is an S-L indirect band gap of 0.518 eV in the vicinity of Fermi surface. Indirect-to-direct band gaps and an unstable-to-stable transition are observed in bulk Fe2Si as strain is applied. In the range −11% to 11% (excluding zero strain), bulk Fe2Si has stable half-metallic ferromagnetism, the spin polarization at the Fermi surface is 100%, and the magnetic moment of the Fe2Si unit cell is 4.0 μB. The density distribution shows that the spin states of bulk Fe2Si mainly come from the Fe1-3d and Fe3-3d states, indicating that bulk Fe2Si has spin-polarized ferromagnetism. The half-metallic ferromagnetism of bulk Fe2Si is mainly caused by d–d exchange and p–d hybridization, which are not sensitive to strain. It is very important to investigate the effect of changes in the lattice constant on the half-metallic ferromagnetic properties of bulk Fe2Si.

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