The Structural Stabilities and Electronic Properties of Orthorhombic and Rhombohedral LaCrO3 — A First-Principles Study

2012 ◽  
Vol 622-623 ◽  
pp. 734-738
Author(s):  
Qing Gong Song ◽  
Ling Ling Song ◽  
Hui Zhao ◽  
Tong Wei ◽  
Jian Hai Kang
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Ceramic Materials ◽  
Binding Energies ◽  
Nano Materials ◽  
Functional Theory ◽  
Self Consistent Field ◽  
Wide Energy ◽  
Equilibrium Structures

The equilibrium structures of orthorhombic LaCrO3(O-LaCrO3) and rhombohedral LaCrO3(R-LaCrO3) crystals were investigated by using the plane-wave self consistent field (PWSCF) method based on density functional theory (DFT). The optimized lattice parameters for both phases are in accordance with experimental results reported in literature, confirming the reliability of LSDA+U scheme used in the calculations. We have quantificationally investigated the binding energies and electronic properties of these two types of LaCrO3crystals. The negative total energy and binding energies indicate the ground state property and the good structrual stability of O-LaCrO3crystal, which is important for the preparation of nano materials, the synthesis of ceramic materials made of doped O-LaCrO3crytals, as well as their applications in high technology fields, and predict the metastable property of R-LaCrO3crystal. Furthermore, the band structures show that O-LaCrO3is a direct semiconductor with wide energy gap, while R-LaCrO3is an indirect semiconductor with narrow energy gap. The interaction between Cr and O atoms in O-LaCrO3crystal possesses the character of covalent bonding.

STRUCTURAL AND ELECTRONIC PROPERTIES OF FINITE-LENGTH SINGLE-WALLED CARBON AND SILICON CARBIDE NANOTUBES: DFT STUDY

2013 ◽  
Vol 27 (29) ◽  
pp. 1350210 ◽  
Author(s):  
IGOR K. PETRUSHENKO ◽  
NIKOLAY A. IVANOV
Keyword(s):  
Silicon Carbide ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Functional Theory ◽  
Single Walled Carbon ◽  
Silicon Carbide Nanotubes ◽  
Structural And Electronic Properties ◽  
Walled Carbon Nanotubes

This paper presents a systematical analysis of the structure and electronic properties of armchair single-walled carbon nanotubes (SWCNTs) as well as single-walled silicon carbide nanotubes ( SiCNTs ) by using density functional theory. The geometries of all species were optimized at the B3LYP level of theory using the SVP basis set. The different behavior of C – C bonds "parallel" and "perpendicular" to the nanotube axis has been found. The HOMO–LUMO energy gap, ionization potential, electron affinity, electronegativity and hardness of studied tubes were compared. The influence of both SWCNTs and SiCNTs lengths on their electronic properties has been analyzed.

EFFECTS OF SURFACE OXYGEN ON THE ELECTRONIC PROPERTIES OF SILICON NANOCLUSTERS

2006 ◽  
Vol 05 (01) ◽  
pp. 13-21 ◽  
Author(s):  
YING DAI ◽  
BAIBIAO HUANG ◽  
LIN YU ◽  
SHENGHAO HAN ◽  
DADI DAI
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Bridge Structure ◽  
Surface Oxygen ◽  
Silicon Nanoclusters ◽  
Silicon Clusters ◽  
Functional Theory

We have studied the effects of surface oxygen and its bond structure on the electronic properties of silicon nanoclusters by means of density functional theory calculations. The results of the energy gap as a function of the nanocluster size in hydrogen-terminated and oxygen-adsorbed silicon clusters provide a well interpretation of several experiments. The nature of electronic and optical properties of silicon nanoclusters has been discussed and attributed to the oxygen in both the Si=O double bond structure and Si–O–Si bridge structure.

scholarly journals A DFT Study of the Impact of Doping on the Electronic and Optical Properties of Indium Nitride Nanocage

2021 ◽  
Author(s):  
Amarjyoti Das ◽  
Rajesh Kumar Yadav
Keyword(s):  
Optical Properties ◽  
Electronic Properties ◽  
Density Functional ◽  
Chemical Potential ◽  
Energy Gap ◽  
Indium Nitride ◽  
Wavelength Region ◽  
Binding Energies ◽  
Electronic And Optical Properties ◽  
The Impact

Abstract Density functional theory (DFT) calculations are used to investigate the structural, electronic, and optical properties of the significant fullerene-like cage of In12N12 nanoclusters with Zn (group II) and Si (group IV) dopants. In terms of formation energies and binding energies, the structural stability of the nanocages were studied. It has been seen that stability of the structure is slightly increases with the inclusion of doping. The study found that both the dopants significantly reduce the energy gap of the In12N12 nanocluster. The electronic properties of the In12N12 nanocluster seems to be sensitive to dopants, and it could be altered by a specific impurity. Moreover, electronic properties such as density of states (DOS) analysis, dipole moment, HOMO energies, LUMO energies, energy gaps, chemical potential, electron affinity, ionization potential, hardness, and electrophilicity index are also discussed. The optical absorption spectra of pure and doped nanocages were computed using TDDFT formalism. The maximum wavelength of the pure In12N12 nanocage is moved towards higher wavelength region within the infrared region after doping with Zn and Si, indicating a redshift.

A Density Functional Theory Study on the Structures and Electronic Properties of XAln (X = Br, I; n = 3–15) Clusters

2019 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Ming Hui ◽  
Qing-Huai Zhao ◽  
Zhi-Peng Wang ◽  
Shuai Zhang ◽  
Gen-Quan Li
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Chemical Hardness ◽  
Geometrical Structures ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractThe effects of halogen element X (X = Br, I) doping on the geometrical structures and electronic properties of neutral aluminium clusters are systematically studied by utilising the density functional theory calculations. The structures of X-doped clusters show the three-dimensional forms with increasing atomic number except for n = 3 and X (X = Br, I) atom prefer to occupy the surface site of the host Aln clusters. BrAl7 and IAl7 clusters are the most stable geometries. The HOMO-LUMO energy gap and chemical hardness show an odd–even alternative phenomenon. The charges always transfer from the Al atoms to the X (X = Br, I) atom. Finally, the dipole and polarisability are discussed.

A density functional theory study on the structural and electronic properties of PbxSbySez (x + y + z = 2, 3) clusters

2018 ◽  
Vol 32 (03) ◽  
pp. 1850024
Author(s):  
Rengi̇n Peköz ◽  
Şaki̇r Erkoç
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Ground States ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Binding Energies ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Scalene Triangle

The structural and electronic properties of neutral ternary PbxSbySez clusters (x + y + z = 2, 3) in their ground states have been explored by means of density functional theory calculations. The geometric structures and binding energies are systematically explored and for the most stable configurations of each cluster type vibrational frequencies, charges on atoms, energy difference between highest occupied and lowest unoccupied molecular orbitals, and the possible dissociations channels have been analyzed. Depending on being binary or ternary cluster and composition, the most energetic structures have singlet, doublet or triplet ground states, and trimers prefer to form isosceles, equilateral or scalene triangle structure.

Lowest Energy Structures and Electronic Properties of Small Molybdenum Clusters

2005 ◽  
Vol 494 ◽  
pp. 79-82 ◽  
Author(s):  
V. Koteski ◽  
Bozidar Cekić ◽  
N. Novaković ◽  
J. Belošević-Čavor
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
First Principles ◽  
Cluster Size ◽  
Density Functional ◽  
Theoretical Data ◽  
Binding Energies ◽  
Functional Theory ◽  
Average Bond

The structural and geometric properties of small Mo clusters are studied by means of first principles density functional theory (DFT) calculations with planewaves and pseudopotentials. The lowest energy structures of Mon (n=2-6) clusters are determined. The evolution of electronic properties with increasing cluster size is discussed. The geometric structure, average bond lengths, and binding energies of the lowest energy isomers are reported and the results are compared with the available experimental and theoretical data.

DFTB Calculation of Si Atomic Chains’ Structures and Electronic Properties

2016 ◽  
Vol 848 ◽  
pp. 494-497
Author(s):  
Xiu Min Xu ◽  
Li Jun Wu ◽  
Lin Zhang
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Tight Binding ◽  
Functional Theory ◽  
Symmetrical Distribution ◽  
Highest Occupied Molecular Orbital ◽  
Atomic Chains ◽  
Lowest Unoccupied Molecular Orbital

In this paper, structures and electronic properties of atomic chains with 5 to 20 silicon atoms and different atomic distances (d = 1.652 ~ 2.752Å) were calculated by the tight-binding method based on density functional theory. The results showed that the majority of the silicon atomic chains were symmetrical structures. When the number of silicon atoms was small, the silicon atomic chains were linear, when the silicon atomic chains had seven or more silicon atoms zigzag structures appeared. With the increase of the distance between atoms, atomic chains were gathering. When the number of silicon atoms was between 10 and 20, the charges on the silicon atoms appeared as a symmetrical distribution. With the increase of the number of atoms, the energy of silicon atomic chains decreased gradually. As the distance between atoms and atomic number changed, HOMO (highest occupied molecular orbital electrons) -LUMO (lowest unoccupied molecular orbital electrons) energy gap changed as well.

AB INITIO CALCULATIONS OF STRUCTURAL AND ELECTRONIC PROPERTIES OF THE COMPOUND Li3AlB2O6

2008 ◽  
Vol 22 (05) ◽  
pp. 343-352
Author(s):  
HAIYING WU ◽  
HONG ZHANG ◽  
XINLU CHENG ◽  
LINGCANG CAI
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Band Structure ◽  
Local Spin Density Approximation ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Equilibrium Structures ◽  
Experimental Values ◽  
Good Agreement

The two equilibrium structures of the compound Li 3 AlB 2 O 6 have been investigated via the minimization of the total energy within Local Spin Density Approximation (LSDA) based on the Density Functional Theory (DFT) in our work. The calculated lattice parameters are all in good agreement with their corresponding experimental values. The relative stability of the two structures are determined. We find that the structure suggested by He et al. is more stable than that proposed by Abdullaev et al. at zero pressure conditions. The reasons for which the structure suggested by He et al. is more stable are also described. Then the electronic properties of the compound Li 3 AlB 2 O 6 including the density of states and energy band structure are successfully obtained and compared for the two structures. We find that the properties of insulator decreases from the structure suggested by He et al. to the structure proposed by Abdullaev et al.

Density functional theory study of structural, magnetic and spectral properties of the CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters

2019 ◽  
Vol 9 (6) ◽  
pp. 570-577
Author(s):  
Yunlong Chen ◽  
Zhenghua Tang ◽  
Chong He ◽  
Yong Sheng
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectroscopy ◽  
Density Functional ◽  
Energy Gap ◽  
Binding Energies ◽  
Chemical Hardness ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo ◽  
Original Cluster

Using Density functional theory (DFT) to study the geometries, stability, magnetic properties and infrared spectroscopy of CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters at the BP86/SDD level. The ground state structures of CrmFen (m + n = 6) and CrmFenCu (m + n = 5) clusters are determined according to the principles of lowest energy and no virtual frequency. On this basis, the structural and chemical stabilities are obtained by the average binding energies (Eb), chemical hardness (η) and HOMO-LUMO energy gap (Eg). The average binding energies show the substitution of a copper atom is beneficial to improve the structural stability; It can be seen Cr4Fe2 and Cr3Fe2Cu have the best chemical stability in the two cluster series from the chemical hardness and HOMO-LUMO energy gap. By calculating the magnetic moment, it is shown that Cr5Fe and CrFe4Cu have large magnetic moments, which can be understood by the spin distribution. Finally, infrared spectroscopy of the clusters are calculated, we find a copper atom substitutes the CrmFen (m + n = 6) does not change the range of vibration frequency a lot because it does not significantly change the molecular structure of the original cluster, but it changes the vibration mode of the original cluster, resulting in the strongest infrared absorption peak intensity of Cr3Fe2Cu being lower than that of Cr3Fe3.

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