scholarly journals Effect of Intrinsic Point Defect on the Magnetic Properties of ZnO Nanowire

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jiangni Yun ◽  
Zhiyong Zhang ◽  
Tieen Yin
Keyword(s):  
Magnetic Properties ◽  
Point Defect ◽  
Density Functional ◽  
Population Analysis ◽  
First Principles Calculation ◽  
Spin Splitting ◽  
Partial Density ◽  
Intrinsic Point Defect ◽  
Zno Nanowire ◽  
Mulliken Population

The effect of intrinsic point defect on the magnetic properties of ZnO nanowire is investigated by the first-principles calculation based on the density functional theory (DFT). The calculated results reveal that the pure ZnO nanowire without intrinsic point defect is nonmagnetic and ZnO nanowire withVO,Zni,Oi,OZn, or ZnOpoint defect also is nonmagnetic. However, a strong spin splitting phenomenon is observed in ZnO nanowire withVZndefect sitting on the surface site. The Mulliken population analysis reveals that the oxygen atoms which are close to theVZndefect do major contribution to the magnetic moment. Partial density states calculation further suggests that the appearance of the half-metallic ferromagnetism in ZnO nanorod withVZnoriginates from the hybridization of the O2p states with Zn 3d states.

scholarly journals Adsorption Mechanism of Cu-Doped SnO2 (110) Surface toward H2 Dissolved in Power Transformer

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Feng Wang ◽  
Jingmin Fan ◽  
Qiuqin Sun ◽  
Qinji Jiang ◽  
She Chen ◽  
...  
Keyword(s):  
Density Functional ◽  
Adsorption Mechanism ◽  
Power Transformer ◽  
Population Analysis ◽  
Electrical Conductance ◽  
Partial Density ◽  
Mulliken Population ◽  
Overlap Population ◽  
Bridge Oxygen ◽  
Partial Atomic Charges

The content of hydrogen is a key quantity in condition assessment and fault diagnosis of power transformer. Based on the density functional theory (DFT), the adsorption mechanism of Cu-doped SnO2 surface toward H2 has been systematically studied in this work. Firstly, the relaxation, the bond length, and overlap population of both the pure and Cu-doped SnO2 are computed. To determine the optimal doping position, the formation energies of four potential sites (i.e., Sn5c, Sn6c, Sn5c-s, and Sn6c-s) are then compared with each other. The adsorption energy and the electronic structure of SnO2 surface are analysed and discussed in detail. Furthermore, to estimate the partial atomic charges and the electrical conductance, the Mulliken population analysis is also performed. It has been found that the bridge oxygen is the most favourable position. The partial density of states of H2 after adsorption is broadened and shifted close to the Fermi level. A large amount of charges would be transferred and then released back into its conduction band, leading to the reduction of resistance and the enhancement of sensitivity toward H2. The results of this work provide references for SnO2-based sensor design.

Fe-DOPED Ga12N12 CLUSTERS: ELECTRONIC AND MAGNETIC PROPERTIES

2013 ◽  
Vol 27 (30) ◽  
pp. 1350222 ◽  
Author(s):  
PENGFEI LU ◽  
CHENGJIE WU ◽  
ZIXIANG CONG ◽  
YILUAN LI ◽  
XIANLONG ZHANG ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
The Density Functional Theory ◽  
Endohedral Doping

In this paper, we have investigated the structural, electronic and magnetic properties of Ga 12 N 12 cluster doped with monodoped and bidoped Fe atoms within the density functional theory (DFT). Substitutional, exohedral and endohedral doping are considered. It is observed that both monodoped and bidoped clusters tend to be in exohedral doping. Mulliken population analysis is performed to obtain the charge transfer and magnetic moment. The magnetic moment is mainly derived from 3d orbitals of Fe atom for all isomers, while the magnetic properties would rely on the Fe – Fe distance.

Electronic Structure and Ferromagnetic Properties of Doped Calcium Sulfide Ca1−xTMxS (TM = V, Cr and Co)

SPIN ◽  
2020 ◽  
Vol 10 (02) ◽  
pp. 2050013 ◽  
Author(s):  
Amina Aiche ◽  
Abdelkader Tadjer ◽  
Hadj Moulay Ahmed Mazouz ◽  
Bendouma Doumi ◽  
Houari Khachai
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Double Exchange ◽  
Ferromagnetic State ◽  
Spin Splitting ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Half Metallic

The electronic structure and magnetic properties of diluted Ca[Formula: see text]TMxS (TM[Formula: see text][Formula: see text][Formula: see text]V, Cr and Co) in the rocksalt structure at concentrations [Formula: see text], 0.125 and 0.25 were studied using the full-potential linearized augmented plane wave approximation of the density functional theory with the Wu-Cohen generalized gradient approximation (WC-GGA) and the Tran–Blaha-modified Becke–Johnson (TB-mBJ) potential. Features such as lattice constant, bulk modulus, spin-polarized band structures, total and local densities of states and magnetic properties have been computed. The electronic structure show that Ca[Formula: see text](V, Cr)xS at all the studied concentrations and the diluted Ca[Formula: see text]CoxS with [Formula: see text] compounds are half-metallic ferromagnets with spin polarization of 100%. The calculated total magnetic moments for Ca[Formula: see text]VxS and Ca[Formula: see text]CoxS show the same integer value of 3[Formula: see text][Formula: see text] per formula unit and Ca[Formula: see text]CrxS exhibit a total magnetic moment of 4[Formula: see text][Formula: see text], which confirm the half-metallic behavior of these compounds. We also calculated the values of the band edge spin splitting of the valence and conduction bands and the exchange constants. We have found that the ferromagnetic state is stable by the p-d exchange associated with the double-exchange mechanism. The diluted Ca[Formula: see text](V,Cr,Co)xS are found to be new promising candidates for spintronic applications.

scholarly journals Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Zhang ◽  
Xu ◽  
Hu ◽  
He ◽  
Tian ◽  
...  
Keyword(s):  
Sodium Oleate ◽  
Density Functional ◽  
Population Analysis ◽  
Water Molecules ◽  
Mulliken Population ◽  
Flotation Reagents ◽  
Functional Theory ◽  
Rigorous Study ◽  
Adsorption Energies ◽  
Hydroxylated Surface

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.

Structures, electronic and magnetic properties of the MnnS and Mnn−1S2 (n = 1–6) clusters

2019 ◽  
Vol 33 (22) ◽  
pp. 1950254 ◽  
Author(s):  
Zhi Li ◽  
Zhen Zhao ◽  
Qi Wang ◽  
Tong-Tong Shi
Keyword(s):  
Magnetic Properties ◽  
Ground State ◽  
First Principles ◽  
Steel Industry ◽  
Population Analysis ◽  
Total Spin ◽  
Spontaneous Generation ◽  
Mulliken Population ◽  
Electronic And Magnetic Properties ◽  
Homo Lumo

To understand sulfide inclusions in the steel industry, the structures, stabilities, electronic and magnetic properties of the Mn[Formula: see text]S and Mn[Formula: see text]S2 (n=1–6) clusters are investigated by using first-principles. The results show that the S atoms prefer to occupy the outside surface center of the Mn[Formula: see text] (n = 3–6) clusters. Chiral isomers are occurred to the Mn5S2 isomers. The Mn2S, Mn2S2 clusters are more stable than their neighbors. However, the MnS, S2, and Mn5I2 clusters possess higher dynamic stability than their neighbors by the HOMO–LUMO gaps. The Mn[Formula: see text]S and Mn[Formula: see text]S2 (n = 1–6) clusters prefer to spontaneous generation by Gibbs free energy. A few 4s orbital electrons of Mn atoms transferred to the S atoms by Mülliken population analysis. For the other Mn[Formula: see text]S (n = 1–6) clusters, the spin density (17.256) of the ground-state Mn6S clusters is the largest. For the Mn[Formula: see text]S2 (n = 1–6) clusters, the total spin (9.604) of the ground-state Mn2S2 cluster is the largest.

Site Preference of Refractory Elements in Ni-Based Single-Crystal Superalloys Alloying with Ru: From First Principles

2012 ◽  
Vol 554-556 ◽  
pp. 3-12
Author(s):  
Jian Jun Cui ◽  
Fei Sun ◽  
Jian Xin Zhang
Keyword(s):  
Binding Energy ◽  
Single Crystal ◽  
First Principles ◽  
First Principles Calculation ◽  
Partial Density ◽  
Site Preference ◽  
Strengthening Effect ◽  
Mulliken Population ◽  
Calculation Results ◽  
Partitioning Behavior

A first principles calculation method was used to investigate the site preference of Ruthenium (Ru) at the γ/γ′ interface in Ni-based single-crystal superalloys. The calculation results show that the addition of Ru can decrease the total energy and the binding energy of γ/γ′ interface, which may result in an improved microstructure stability of Ni-based single-crystal superalloys. Moreover, by calculation, it is also found that Ru can stabilize both γ and γ′ phases and have a preference for Ni site at the coherent γ/γ′ interface. When Ru substitutes the central Ni at the γ/γ′ interface, a reverse partitioning of W, Re and Cr occurs; while the partitioning behavior of Mo is not affected. The influence of Ru on the partitioning behavior of W, Re and Cr in γ′-Ni3Al was studied by Dmol3 calculation as well. The calculation results show that W, Re and Cr have a preference for Ni site in γ′- Ni3Al with Ru alloying. When Ru substitutes the central Ni atom, the site preference of W, Re and Cr varies accordingly. Furthermore, electronic structure analysis of γ/γ′ interface and γ′-Ni3Al in terms of Mulliken population and partial density of states (PDOS) was performed to understand the alloying mechanism of Ru in Ni-based single-crystal superalloys. The results show that the strengthening effect of Ru alloying is mainly due to the reduction in binding energy of Ru as well as a p-orbital hybridization between Ru and the host atoms.

scholarly journals Comparative DFT study on selective hydrogenation of acrolein catalyzed by pure Mo2C(001) and Pt/Mo2C(001)

2021 ◽  
Author(s):  
Jinrong Wu ◽  
Yanping Huang ◽  
Weiyan Wang ◽  
Wensong Li ◽  
Zhengke Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Allyl Alcohol ◽  
Active Sites ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Elementary Reactions ◽  
Bond Hydrogenation

Abstract In this paper, Density Functional Theory (DFT) calculations were conducted to study the adsorption and stepwise hydrogenation of acrolein (CH 2 =CHCH=O) on pure Mo 2 C(001) and Pt/Mo 2 C(001). The electronic properties were investigated by Mulliken population analysis. The results showed that Mo atoms obtained some electrons from surrounding Pt and C atoms, thereby enhancing the hydrogenation activity of Mo atoms around Pt atoms and forming local active sites dominated by Mo atoms around Pt atoms. As a result, the adsorption energy of the species on Pt/Mo 2 C(001) is generally higher than that on Mo 2 C(001), and the activation energies of the elementary reactions involved in stepwise hydrogenation of acrolein on Pt/Mo 2 C(001) are lower than those on Mo 2 C(001). Moreover, Pt/Mo 2 C(001) exhibits higher selectivity for C=O bond hydrogenation than Mo 2 C(001) and produces more allyl alcohol.

TiO2/GRAPHENE OXIDE HETEROSTRUCTURES FOR GAS-SENSING: INTERACTION OF NITROGEN DIOXIDE WITH THE PRISTINE AND NITROGEN MODIFIED NANOSTRUCTURES INVESTIGATED BY DFT

2019 ◽  
Vol 26 (04) ◽  
pp. 1850170 ◽  
Author(s):  
AMIRALI ABBASI ◽  
JABER JAHANBIN SARDROODI
Keyword(s):  
Graphene Oxide ◽  
Charge Transfer ◽  
Density Of States ◽  
Density Functional ◽  
Gas Sensing ◽  
Population Analysis ◽  
Molecular Orbitals ◽  
Molecular Orbital Calculations ◽  
Mulliken Population ◽  
A Charge

The gas response of metal oxide-based sensors depends strongly on its adsorption properties. To explore the potential sensing capability of pristine and nitrogen modified TiO2/graphene oxide (GO) heterostructures, the adsorption of NO2 molecule on the N-doped nanocomposites was investigated using density functional theory (DFT) calculations. Six possible configurations were simulated based on the estimated adsorption energies. The binding sites were located over the oxygen, doped nitrogen and five-fold coordinated titanium atoms of TiO2. The electronic properties including atomic Mulliken population, projected density of states and molecular orbitals were investigated in detail. The N–O bonds of the NO2 molecule were significantly increased after the adsorption process. The adsorption of NO2 molecule on the N-doped nanocomposite is more energetically favorable than the adsorption on the undoped one. The results suggest that NO2 chemisorbs on the considered nanocomposites. Mulliken population analysis reveals a noticeable charge transfer from the nanocomposite to the molecule, which indicate that NO2 acts as a charge acceptor. Molecular orbital calculations show that the highest occupied molecular orbitals (HOMOs) of the studied systems were mainly localized on the adsorbed NO2 molecule. The significant overlaps in the projected density of states (PDOS) spectra of the interacting atoms confirm the formation of chemical bonds between them. There is a direct relationship between the results of charge transfer and sensing responses. N-doped nanocomposites have better sensing response than the undoped ones. The results highlight the possibility to develop innovative highly efficient NO2 sensors based on novel TiO2/GO nanocomposites.

scholarly journals Opto-Electronic Investigation of Rubidium Based Fluoro-Perovskite for Low Birefringent Lens Materials

2017 ◽  
Vol 1 (1) ◽  
pp. 37-48
Author(s):  
M. A. Iqbal ◽  
N. Erum
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Structural Parameters ◽  
First Principles Calculation ◽  
Partial Density ◽  
Generalized Gradient ◽  
Contour Maps ◽  
Data Assessment ◽  
Method Optimization ◽  
Quantum Mechanical Effects

In this communication, systematic first principles calculation has been scrutinize to evaluate bonding nature, structural, electronic, and optical properties of RbHgF3. The findings are based on total energy calculations where Khon Sham (KS) equation is solved by means of density functional theory (FP-LAPW) method. Optimization of structural parameters is done with variety of approximations, which corroborates through comparison with available experimental data. Assessment of band profile through GGA plus Trans-Blaha modified Becke–Johnson (TB-mBJ) potential highlights underestimation of bandgap with traditional Generalized Gradient approximations. Specific contribution of particular states on electronic properties is investigated by means of total and partial density of states while contour maps of electron density are used to sightsee bonding character and it is evaluated that emphasized compound is (M-Γ) indirect bandgap material with mixed ionic and covalent bonding character. Additionally attention is paid to absorption and reflection spectra of RbHgF3fluoroperovskite by reconnoitering optical properties, which shows extensive absorption and reflection in high frequency regions. Expectantly, current study would benchmark various quantum mechanical effects, which must be taken into account to understand and utilize RbHgF3 in fabricating practical devices.

Theoretical study of the geometrical and electronic properties of Be2Mg+ n (n = 1–11) clusters

2019 ◽  
Vol 9 (7) ◽  
pp. 778-785 ◽  
Author(s):  
Ben-Chao Zhu ◽  
Zhang Yu ◽  
Wang Ping ◽  
Lu Zeng ◽  
Shuai Zhang
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Population Analysis ◽  
Dft Method ◽  
Mulliken Population ◽  
Functional Theory ◽  
Fragmentation Energy ◽  
Average Binding Energy ◽  
Ground State Structures

By using Density Functional Theory (DFT) method at the B3LYP/6-311G level, the structures, stabilities, and electronic properties of cationic Be2Mg+ n (n = 1–11) clusters have been systematically studied. The optimized geometry show that the ground state structures of cationic Be2Mg+ n (n = 1–11) clusters favor 3D structures except n = 1, 2. Furthermore, the average binding energy E b, the second-order energy differences Δ2E, the fragmentation energy Ef and the HOMO-LUMO energy Egap of the ground state of cationic Be2Mg– n (n = 1–11) clusters are calculated, the final results indicate that Be2Mg+6 and Be2Mg+9 clusters have a higher stability than other clusters. Additionally, the NCP, NEC and Mulliken population analysis reveal that the charges in cationic Be2Mg+ n (n = 1–11) clusters transfer from Mg atom to Be atoms, and strong sp hybridizations are presented in Be atoms of Be2Mg+ n clusters. Finally, the polarizability analysis indicates that the nuclei and electronic clouds of clusters are affected by external field with the increase of cluster size.

Sign in / Sign up

Export Citation Format

Share Document