First-principles study on the thermodynamic, mechanical and magnetic properties of the Fe-N phases

2020 ◽  
Vol 34 (17) ◽  
pp. 2050156
Author(s):  
Zhi Li ◽  
Zhen Zhao ◽  
Tong-Tong Shi ◽  
Xi-Min Zang
Keyword(s):  
First Principles ◽  
Population Analysis ◽  
Magnetic Moments ◽  
Iron Nitrides ◽  
Anisotropic Behavior ◽  
Ductile Phase ◽  
Mulliken Population ◽  
Debye Temperatures ◽  
Brittle Phase ◽  
Formation Energies

To clear the intermetallic Fe-N phases, how to effect the strength and magnetic features of iron nitrides thin films, the thermodynamic, mechanical and magnetic attributes of the Fe-N phases have been calculated at Perdew, Burke and Enzerhof (PBE) level. The results show that the [Formula: see text] and [Formula: see text] phases are more stable than the other considered Fe-N phases by the formation energies. [Formula: see text] and [Formula: see text] phases are metastable at 0 K, which can be further decomposed into other more stable phases with temperature decreasing, i.e., [Formula: see text] and [Formula: see text]. [Formula: see text] is the only brittle phase, while [Formula: see text] is the most ductile phase. The [Formula: see text] possesses the highest thermal conductivity by Debye temperatures. The [Formula: see text] possesses the highest anisotropic behavior by [Formula: see text], [Formula: see text] and [Formula: see text] values. The [Formula: see text] and FeN phases possess higher average magnetic moments (MM) than their neighbors. The [Formula: see text] has stronger ionic bond by Mülliken population analysis.

scholarly journals First-Principles Study on Stability and Magnetism ofNimAln(m=1–3,n=1–9) Clusters

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Xiao Zhang ◽  
Bao-Xing Li ◽  
Zhi-wei Ma ◽  
Jiao-jiao Gu
Keyword(s):  
Ground State ◽  
First Principles ◽  
Population Analysis ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
The Other ◽  
Mulliken Population Analysis ◽  
Mixed Species ◽  
Mulliken Population ◽  
Ground State Structures

The investigation on the structures, stabilities, and magnetism ofNimAln(m=1–3,n=1–9) clusters has been made by using first principles. We found some new ground-state structures which had not been found before. These mixed species prefer to adopt three-dimensional (3D) structures starting from four atoms. All the ground-state structures for the Ni-Al clusters are different from those of the corresponding pure Al clusters with the same number of atoms except for three atoms. The Mulliken population analysis shows that some charges transfer from the Al atoms to the Ni atoms.NiAln(n = odd number) cations, Ni2Al6neutral, Ni2Al1and Ni3Al cations and anions, and Ni3Al5anion have the magnetic moments of 2 μB. The magnetic moments of NiAl4and NiAl6cluster neutrals and cations are 2 μBand 3 μB, respectively. All the other cluster neutrals and ions do not have any nontrivial magnetic moments. The 3d electrons in Ni atoms are mainly responsible for the magnetism of the mixed Ni-Al clusters.

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.

First-principles study of Cu adsorption on vacancy-defected/Au-doped graphene

2018 ◽  
Vol 32 (11) ◽  
pp. 1850139 ◽  
Author(s):  
Yang Liu ◽  
Libao An ◽  
Liang Gong
Keyword(s):  
First Principles ◽  
Population Analysis ◽  
First Principles Calculation ◽  
Matrix Composites ◽  
Mulliken Population ◽  
Vacancy Defects ◽  
Subsequent Investigation ◽  
Doped Graphene ◽  
The Stability ◽  
P Type

To enhance the interaction between Cu and graphene in graphene reinforced Cu matrix composites, the first principles calculation was carried out to study the adsorption of Cu atoms on graphene. P-type doping and n-type doping were formed, respectively, on vacancy-defected and Au-doped graphene based on band structure analysis, and this was verified by subsequent investigation on density of states. A computation on charge transfer confirmed that p-type doping could promote the electron transport between Cu and graphene, while n-type doping would prevent it. In addition, adsorption energy and Mulliken population analysis revealed that both vacancy defects and Au doping could improve the stability of the Cu–graphene system. The research conducted in this paper provides useful guidance for the preparation of Cu/graphene composites.

scholarly journals Half-Metallicity and Magnetism of the Quaternary Heusler Compound TiZrCoIn1−xGex from the First-Principles Calculations

2019 ◽  
Vol 9 (4) ◽  
pp. 620 ◽  
Author(s):  
Ying Chen ◽  
Shaobo Chen ◽  
Bin Wang ◽  
Bo Wu ◽  
Haishen Huang ◽  
...  
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Valence Electrons ◽  
The Stability ◽  
Formation Energies ◽  
Quaternary Heusler Compound ◽  
Ge Doping

The effects of doping on the electronic and magnetic properties of the quaternary Heusler alloy TiZrCoIn were investigated by first-principles calculations. Results showed that the appearance of half-metallicity and negative formation energies are associated in all of the TiZrCoIn1−xGex compounds, indicating that Ge doping at Z-site increases the stability without damaging the half-metallicity of the compounds. Formation energy gradually decreased with doping concentration, and the width of the spin-down gap increased with a change in Fermi level. TiZrCoIn0.25Ge0.75 was found to be the most stable half-metal. Its Fermi level was in the middle of the broadened gap, and a peak at the Fermi level was detected in the spin majority channel of the compound. The large gaps of the compounds were primarily dominated by the intense d-d hybridization between Ti, Zr, and Co. The substitution of In by Ge increased the number of sp valence electrons in the system and thereby enhanced RKKY exchange interaction and increased splitting. Moreover, the total spin magnetic moments of the doped compounds followed the Slater–Pauling rule of Mt = Zt − 18 and increased from 2 μB to 3 μB linearly with concentration.

First Principles Study of Surface Properties for Silicon Carbide-Derived Structures

2012 ◽  
Vol 433-440 ◽  
pp. 306-312
Author(s):  
Hong Ge Liu ◽  
Rui Jun Zhang ◽  
Hong Yan Jin ◽  
Qiu Xiang Liu
Keyword(s):  
Silicon Carbide ◽  
Surface Properties ◽  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Nanoporous Surface ◽  
Pseudo Potential

Using first-principles ultra-soft pseudo-potential approach of the plane wave based on the density functional theory (DFT), we investigated the surface properties for silicon carbide-derived structure (i.e. SiCDS). The calculated results show that, movement of C and Si atoms caused by Si removal results in surface structural changing, and a nanoporous surface feature can be observed on the SiCDS surfaces when more Si atoms are removed. The mulliken population analysis indicates that the Si removal leads to the stronger chemical bonds between C–Si and the formation of new stronger chemical bands between C–C. From the density of states, as the Si removal proportion increases, C2p becomes gradually dominant in the SiCDS surface state electrons. Moreover, the Si removal leads to evidently different band gaps, indicating that the conductivity for SiCDS surface structures can be adjusted through the Si removal.

CO Adsorption on the AunS(n=1~6) Clusters: The First-Principles Study

2011 ◽  
Vol 341-342 ◽  
pp. 42-47
Author(s):  
Shui Lian Chi ◽  
Ming Chen ◽  
Song Lin Peng
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Co Adsorption ◽  
Bimetallic Clusters ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Au Clusters ◽  
Adsorption Energies

Density functional theory (DFT) calculations are performed to investigate CO bonded on the AunS (n=1~6) bimetallic clusters. It is found that the adsorption energies of CO on the AunS(n=1~6) clusters are greater than those on the pure Au clusters of corresponding sizes. This means that doped S atom can enhance CO adsorption on the Au clusters. Furthermore, through the Mulliken population analysis, we can see that charges transfer from the Au clusters to S atom, while charges donate to the Au clusters from the CO in CO/AunS sytem.

Structures, elastic, electronic properties and phase stability of Ni–Sc intermetallic compounds from first-principles investigation

2018 ◽  
Vol 32 (24) ◽  
pp. 1850262 ◽  
Author(s):  
Yali Wu ◽  
Xuefeng Guo
Keyword(s):  
Shear Modulus ◽  
Electronic Properties ◽  
Intermetallic Compounds ◽  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Ductile Phase ◽  
Covalent Bonds ◽  
Debye Temperatures

First-principles method based on density functional theory has been performed to study the lattice structures, elastic properties, Debye temperatures, electronic properties and phase stability of Ni–Sc intermetallic compounds systematically. The calculated lattice parameters are close to available experimental data. The analysis results of formation enthalpies indicate that the Ni–Sc compounds are all thermodynamically stable and NiSc is the most stable. Besides, these compounds are also mechanically stable according to the mechanical stability criterion. The obtained shear modulus G and Young’s modulus E show that Ni5Sc is the stiffest and the most covalent compound. The discussion about G/B (the ratio of shear modulus to bulk modulous), Poisson’s ratio [Formula: see text] and Cauchy pressure demonstrate that all Ni–Sc compounds are ductile and NiSc2 is the most ductile phase, followed by NiSc. The results of Debye temperatures indicate that Ni5Sc has the stronger covalent bonds than others. Finally, the electronic properties are investigated to reveal the underlying mechanical properties.

First Principles Study of Metal-Encapsulated Silicene-Like Nanotubes

2011 ◽  
Vol 320 ◽  
pp. 421-426
Author(s):  
Chuan Hui Zhang ◽  
Qiong Ran ◽  
Jiang Shen
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Structural Stability ◽  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Magnetic Moments ◽  
Functional Theory ◽  
First Principles Study

We systematically investigated the structural stability and electronic properties of silicene-like nanotubes by potassium atoms encapsulated using density functional theory. The calculations show that all the structures of KnSi8(n+1) (n=2-12) nanowires are stable, the structural stable is proportional to the lengths of the nanowires. Electronic population analysis shows that K atoms gain electrons and Si atoms lose electrons as a whole, some electrons transferred from Si to K atoms. Because the peaks of d levels in DOS are contribution from the 3d hybridization levels of K and Si atoms, the magnetic moments derived from the orbitals hybridization. Maybe these kinds of nanowires will play an important role in spintronics and nanoelectronics.

scholarly journals Ni Oxidation State and Ligand Saturation Impact on the Capability of Octaazamacrocyclic Complexes to Bind and Reduce CO2

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4139
Author(s):  
Barbora Vénosová ◽  
Ingrid Jelemenská ◽  
Jozef Kožíšek ◽  
Peter Rapta ◽  
Michal Zalibera ◽  
...  
Keyword(s):  
Quantum Theory ◽  
Oxidation State ◽  
Central Atom ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Theoretical Methods ◽  
Ni Oxidation ◽  
Shed Light

Two 15-membered octaazamacrocyclic nickel(II) complexes are investigated by theoretical methods to shed light on their affinity forwards binding and reducing CO2. In the first complex 1[NiIIL]0, the octaazamacrocyclic ligand is grossly unsaturated (π-conjugated), while in the second 1[NiIILH]2+ one, the macrocycle is saturated with hydrogens. One and two-electron reductions are described using Mulliken population analysis, quantum theory of atoms in molecules, localized orbitals, and domain averaged fermi holes, including the characterization of the Ni-CCO2 bond and the oxidation state of the central Ni atom. It was found that in the [NiLH] complex, the central atom is reduced to Ni0 and/or NiI and is thus able to bind CO2 via a single σ bond. In addition, the two-electron reduced 3[NiL]2− species also shows an affinity forwards CO2.

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