scholarly journals Structural, Electronic and Vibrational Properties of YAl3(BO3)4

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 545 ◽  
Author(s):  
Aleksandr S. Oreshonkov ◽  
Evgenii M. Roginskii ◽  
Nikolai P. Shestakov ◽  
Irina A. Gudim ◽  
Vladislav L. Temerov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Band Gap ◽  
Density Functional ◽  
Dielectric Material ◽  
Electronic Band Structure ◽  
Vibrational Properties ◽  
Electronic Band ◽  
Functional Theory ◽  
Dynamical Properties ◽  
Indirect Band Gap

The crystal structure of YAl3(BO3)4 is obtained by Rietveld refinement analysis in the present study. The dynamical properties are studied both theoretically and experimentally. The experimental Raman and Infrared spectra are interpreted using the results of ab initio calculations within density functional theory. The phonon band gap in the Infrared spectrum is observed in both trigonal and hypothetical monoclinic structures of YAl3(BO3)4. The electronic band structure is studied theoretically, and the value of the band gap is obtained. It was found that the YAl3(BO3)4 is an indirect band gap dielectric material.

scholarly journals Влияние размерных эффектов на электронную структуру гексагонального теллурида галлия

2018 ◽  
Vol 60 (9) ◽  
pp. 1645
Author(s):  
А.В. Кособуцкий ◽  
С.Ю. Саркисов
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Bulk Material ◽  
Structural Parameters ◽  
Van Der Waals Interactions ◽  
Electronic Band ◽  
Functional Theory ◽  
Lower Conduction Band ◽  
The Density Functional Theory ◽  
Indirect Band Gap

AbstractUsing methods of the density functional theory, the electronic band structure of a hexagonal modification of the layered GaTe semiconductor has been calculated. The structural parameters of a bulk crystal with the β-polytype symmetry have been determined taking into account van der Waals interactions and agree with experimental data for polycrystalline films within 2%. Estimates for the position of extrema of the upper valence band and the lower conduction band have been obtained with respect to the vacuum level for bulk β-GaTe and for ultrathin plates with the number of elementary layers ranging from 1 to 10, which corresponds to a thickness range of 0.5–8 nm. The calculations demonstrate that hexagonal GaTe is an indirect band gap semiconductor with a forbidden band width varying from 0.8 eV in the bulk material to 2.3 eV in the monolayer.

The Electronic Band Structure and Vibrational Properties of Cubic BxIn1-xN Alloy

2013 ◽  
Vol 446-447 ◽  
pp. 98-103
Author(s):  
Nnamdi Omehe ◽  
Divine Ojuh
Keyword(s):  
Band Structure ◽  
Band Gap ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Band Structure Calculation ◽  
Gw Approximation ◽  
Electronic Band ◽  
Phonon Band ◽  
Zone Centre ◽  
Indirect Band Gap

We have performed the electronic and phonon band structures of BxIn1-xN for various concentration of Boron using the pseudopotential method. The electronic band structure calculation was done using the GW approximation while the phonon band structure was done using the density functional perturbation theory. All calculations were done within the frame work of the density functional theory (DFT). From our calculations, the direct band gap for B0.25In0.75N, B0.5In0.5N and B0.75In0.25N were found to be 0.024eV, 2.2 eV and 6.01 eV respectively while the indirect band gap obtained were 0.59 eV, 3.24 eV and 6.9 eV. For the phonon calculations, it was also observed that an increase in the Boron content results in corresponding increase in the frequency of the topmost LO at the zone centre. For B0.25In0.75N, B0.5In0.5N and B0.75In0.25N, the topmost LO obtained were 735 cm-1, 885 cm-1 and 1105 cm-1 respectively. We also saw that as the Boron concentration decreases, the number of optical bands across which the acoustic bands overlap increases.

scholarly journals Effect of Nitrogen Impurity on Electronic Properties of Boron Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Sandeep Kumar Jain ◽  
Pankaj Srivastava
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Nitrogen Doping ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Functional Theory ◽  
Impurity Atoms ◽  
Nitrogen Impurity ◽  
First Time

For the first time we present electronic band structure and density of states for nitrogen doped hexagonal ultrathin boron nanotubes in the framework of density functional theory. The considered models of nanotubes below 5 Å diameter are armchair (3,3), zigzag (5,0), and chiral (4,2). The impurity chosen for the study is nitrogen and concentration of impurity atoms is limited to two. The study reveals that (3,3) BNT retains its metallic nature after nitrogen doping. However, metallicity gets increased which is attributed by the excess electrons of nitrogen. Further, it also brings out that (5,0) BNT which is originally metal transforms into semiconductor after nitrogen interaction and the band gap at G point increases with the impurity. Moreover, the band gap of (4,2) BNT reduces significantly and turns into semimetal for nitrogen doping. Thus, the nitrogen impurity has the predominant effect on the electronic properties of BNTs and therefore can be regarded as suitable candidates for nanoelectronic and field emission devices.

scholarly journals Ab initio calculations of electronic band structure of CdMnS semimagnetic semiconductors

Doklady BGUIR ◽  
2022 ◽  
Vol 19 (8) ◽  
pp. 45-49
Author(s):  
M. А. Mehrabova ◽  
N. T. Panahov ◽  
N. H. Hasanov
Keyword(s):  
Crystal Structure ◽  
Band Structure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Band Gap ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Spin Density Approximation ◽  
Electronic Band ◽  
Semimagnetic Semiconductors

This work is devoted to theoretical investigations of Cd1-xMnxS semimagnetic semiconductors (SMSC). The purpose of this work was to calculate the electronic band structure of ideal and defective Cd1- xMnxS SMSC in both antiferromagnetic (AFM) and ferromagnetic (FM) phases. Ab initio, calculations are performed in the Atomistix Toolkit (ATK) program within the Density Functional Theory (DFT) and Local Spin Density Approximation (LSDA) on Double Zeta Double Polarized (DZDP) basis. We have used Hubbard U potential UMn = 3.59 eV for 3d states for Mn atoms. Supercells of 8 and 64 atoms were constructed. After the construction of Cd1-xMnxS (x = 6.25 %; 25 %) supercells and atom relaxation and optimization of the crystal structure were carried out. Electronic band structure and density of states were calculated, the total energy has been defined in antiferromagnetic (AFM) and ferromagnetic (FM) phases. Our calculations show that the band gap increases with the increase in Mn ion concentration. It has been established that Cd or S vacancy in the crystal structure leads to the change of band gap, Fermi level shifts towards the valence or conduction band.

FIRST-PRINCIPLES STUDIES ON THE ELECTRONIC STRUCTURE OF LuPd2Si2

2009 ◽  
Vol 23 (32) ◽  
pp. 5929-5934 ◽  
Author(s):  
T. JEONG
Keyword(s):  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Spin Orbit Coupling ◽  
Electronic Band ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Scheme

The electronic band structure of LuPd 2 Si 2 was studied based on the density functional theory within local density approximation and fully relativistic schemes. The Lu 4f states are completely filled and have flat bands around -5.0 eV. The fully relativistic band structure scheme shows that spin–orbit coupling splits the 4f states into two manifolds, the 4f7/2 and the 4f5/2 multiplet.

scholarly journals Ab-initio study of the orthorhombic ndmno3 perovskite

2014 ◽  
Vol 70 (a1) ◽  
pp. C1806-C1806
Author(s):  
Samir Bentata ◽  
Bouabdellah Bouadjemi ◽  
Tayeb Lantri ◽  
Wissem Benstaali
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Total Density ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Functional Theory ◽  
Half Metallic ◽  
Generalized Gradient Approximation ◽  
Ferromagnetic Ground State ◽  
Total Density Of States

We investigate the structural, electronic and magnetic properties of the orthorhombic Perovskite oxyde NdMnO3 through density-functional-theory (DFT) calculations using both generalized gradient approximation GGA+U, where U is on-site Coulomb interaction correction. The electronic band structure, the partial and total density of states (DOS) and the magnetic moment are determined. The results show a half-metallic ferromagnetic ground state for the orthorhombic NdMnO3.

Electronic Band Structure of Cubic Silicon Carbide Nanowires

2008 ◽  
Vol 600-603 ◽  
pp. 575-578 ◽  
Author(s):  
A. Miranda ◽  
A. Estrella Ramos ◽  
M. Cruz Irisson
Keyword(s):  
Silicon Carbide ◽  
Band Structure ◽  
Band Gap ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Thickness Variation ◽  
Hydrogen Atoms ◽  
Electronic Band ◽  
Cubic Silicon Carbide

In this work, the effects of the diameter and morphology on the electronic band structure of hydrogenated cubic silicon carbide (b-SiC) nanowires is studied by using a semiempirical sp3s* tight-binding (TB) approach applied to the supercell model, where the Si- and C-dangling bonds on the surface are passivated by hydrogen atoms. Moreover, TB results (for the bulk) are compared with density functional calculations in the local density approximation. The results show that though surface morphology modifies the band gap, the change is more systematic with the thickness variation. As expected, hydrogen saturation induces a broadening of the band gap energy because of the quantum confinement effect.

Theoretical Investigation on Electronic Properties of ZnO Crystals Using DFT-Based Calculation Method

2015 ◽  
Vol 1112 ◽  
pp. 41-44 ◽  
Author(s):  
Yudi Darma ◽  
Freddy Giovanni Setiawan ◽  
Muhammad Aziz Majidi ◽  
Andrivo Rusydi
Keyword(s):  
Band Gap ◽  
Valence Band ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Valence Band Maximum ◽  
Band Gaps ◽  
Generalized Gradient ◽  
Strong Electron ◽  
Electronic Band ◽  
Rocksalt Structure

We study the electronic band structure and density of states (DOS) on ZnO material in various crystal structures : wurtzite (W), zincblende (ZB), and rocksalt (RS) phases. Calculations are based on Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA) for exchange-correlation functional and Hubbard correction to consider the strong electron correlations in 3d orbitals. After structural optimization, GGA results show that wurtzite and zincblende structures have a direct band gap of 0.749 eV and 0.637 eV, respectively, whereas rocksalt structure has an indirect band gap of 0.817 eV. Symmetrical shape of total DOS for spin up and spin down electrons indicates a zero total magnetic moment. For all ZnO structures, the upper valence band is formed by hybridization among O 2p and Zn 3d orbitals, while lower valence and conduction band are primarily filled by O 2s and Zn 4s, respectively. The GGA+U approach is found to improve the calculated band gaps and correct the position of Zn 3d state below Valence Band Maximum (VBM). From GGA+U, the band gaps for W-ZnO, ZB-ZnO, and RS-ZnO are 1.12 eV, 1.00 eV, and 1.11 eV, respectively.

Ab Initio Electronic Structure Studies of CuO Multiferroics

2012 ◽  
Vol 488-489 ◽  
pp. 129-132 ◽  
Author(s):  
C. Kanagaraj ◽  
Baskaran Natesan
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Metallic State ◽  
Magnetic Ground State ◽  
Electronic Band ◽  
Functional Theory ◽  
High Tc ◽  
Band Structure Calculations ◽  
Structure Calculations

We have performed detailed structural, electronic and magnetic properties of high - TC multiferroic CuO using first principles density functional theory. The total energy results revealed that AFM is the most stable magnetic ground state of CuO. The DOS and electronic band structure calculations show that in the absence of on-site Coulomb interaction (U), AFM structure of CuO heads to a metallic state. However, upon incorporating U in the calculations, a band gap of 1.2 eV is recovered. Furthermore, the Born effective charges calculated on Cu does not show any anomalous character.This suggests that the polarization seen in CuO could be attributed to the spin induced AFM ordering effect.

Sign in / Sign up

Export Citation Format

Share Document