Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

First-Principles Study of Structural, Electronic and Magnetic Properties of Metal-Centered Tetrahexahedral V₁₅? Cluster.

ABSTRACT: The V-centered bicapped hexagonal antiprism structure (A), as the most stable geometry of the cationic V₁₅? cluster, is determined by using infrared multiple photo dissociation (IR-MPD) in combination with density functional theory computations. It is found that the A structure can be stabilized by 18 delocalized 3c-2e ?-bonds on outer V? triangles of the bicapped hexagonal antiprism surface and 12 delocalized 4c-2e ?-bonds on inner trigonal pyramidal V? moiety, and the features are related to the strong p-d hybridization of the cluster. The total magnetic moments on the cluster are predicted to be 2.0 µ_B, which come mainly from the central vanadium atom.

SUBMITTER: Li X

PROVIDER: S-EPMC5535230 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

First-Principles Study of Structural, Electronic and Magnetic Properties of Metal-Centered Tetrahexahedral V15⁺ Cluster.

Li Xiaojun X Ren Hongjiang H Huang Xinwei X Li Shuna S

Nanomaterials (Basel, Switzerland) 20170630 7

The V-centered bicapped hexagonal antiprism structure (A), as the most stable geometry of the cationic V15⁺ cluster, is determined by using infrared multiple photo dissociation (IR-MPD) in combination with density functional theory computations. It is found that the A structure can be stabilized by 18 delocalized 3c-2e σ-bonds on outer V₃ triangles of the bicapped hexagonal antiprism surface and 12 delocalized 4c-2e σ-bonds on inner trigonal pyramidal V₄ moiety, and the ...[more]

PMID: 28665337

Similar Datasets

First-principles study on structural, electronic, magnetic and thermodynamic properties of lithium ferrite LiFe5O8.

Project description:Lithium ferrite, LiFe5O8 (LFO), has attracted great attention for various applications, and there has been extensive experimental studies on its material properties and applications. However, no systematic theoretical study has yet been reported, so understanding of its material properties at the atomic scale is still required. In this work, we present a comprehensive investigation into the structural, electronic, magnetic and thermodynamic properties of LFO using first-principles calculations. We demonstrate that the ordered α-phase with ferrimagnetic spin configuration is energetically favourable among various crystalline phases with different magnetic configurations. By applying the DFT + U approach with U = 4 eV, we reproduce the lattice constant, band gap energy, and total magnetization in good agreement with experiments, emphasizing the importance of considering strong correlation and spin-polarization effects originating from the 3d states of Fe atoms. We calculated the phonon dispersions of LFO with ferrimagnetic and non-magnetic states, and subsequently evaluated the Gibbs free energy differences between the two states, plotting the P-T diagram for thermodynamic stability of the ferrimagnetic against non-magnetic state. From the P-T diagram, the Curie temperature is found to be ∼925 K at the normal condition and gradually increase with increasing pressure. Our calculations explain the experimental observations for material properties of LFO, providing a comprehensive understanding of the underlying mechanism and useful guidance for enhancing performance of LFO-based devices.

| S-EPMC9134028 | biostudies-literature

First-principles calculations of structural, electronic, magnetic and elastic properties of Mo2FeB2 under high pressure.

Project description:The structural, electronic, magnetic and elastic properties of Mo2FeB2 under high pressure have been investigated with first-principles calculations. Furthermore, the thermal dynamic properties of Mo2FeB2 were also studied with the quasi-harmonic Debye model. The volume of Mo2FeB2 decreases with the increase in pressure. Using the analysis of the density of the states, atom population and Mulliken overlap population, it is observed that as the pressure increases, the B-B bonds are strengthened and the B-Mo covalency decreases. Moreover, for all pressures, Mo2FeB2 is detected in the anti-ferromagnetic phase and the magnetic moments decrease with the increase in pressure. The calculated bulk modulus, shear modulus, Young's modulus, Poisson's ratio and universal anisotropy index all increase with the increase in pressure. From thermal expansion coefficient analysis, it is found that Mo2FeB2 shows good volume invariance under high pressure and temperature. The examination of the dependence of heat capacity on the temperature and pressure shows that heat capacity is more sensitive to temperature than to pressure.

| S-EPMC6083659 | biostudies-literature

Investigation of structural, electronic and magnetic properties of breathing metal-organic framework MIL-47(Mn): a first principles approach.

Project description:The structural, electronic and magnetic properties of the MIL-47(Mn) metal-organic framework are investigated using first principles calculations. We find that the large-pore structure is the ground state of this material. We show that upon transition from the large-pore to the narrow-pore structure, the magnetic ground-state configuration changes from antiferromagnetic to ferromagnetic, consistent with the computed values of the intra-chain coupling constant. Furthermore, the antiferromagnetic and ferromagnetic configuration phases have intrinsically different electronic behavior: the former is semiconducting, the latter is a metal or half-metal. The change of electronic properties during breathing posits MIL-47(Mn) as a good candidate for sensing and other applications. Our calculated electronic band structure for MIL-47(Mn) presents a combination of flat dispersionless and strongly dispersive regions in the valence and conduction bands, indicative of quasi-1D electronic behavior. The spin coupling constants are obtained by mapping the total energies onto a spin Hamiltonian. The inter-chain coupling is found to be at least one order of magnitude smaller than the intra-chain coupling for both large and narrow pores. Interestingly, the intra-chain coupling changes sign and becomes five times stronger going from the large pore to the narrow pore structure. As such MIL-47(Mn) could provide unique opportunities for tunable low-dimensional magnetism in transition metal oxide systems.

| S-EPMC9049066 | biostudies-literature

Effect of 3d Transition Metal Atom Intercalation Concentration on the Electronic and Magnetic Properties of Graphene/MoS2 Heterostructure: A First-Principles Study.

Project description:The electronic and magnetic properties of graphene/MoS2 heterostructures intercalated with 3d transition metal (TM) atoms at different concentrations have been systematically investigated by first principles calculations. The results showed that all the studied systems are thermodynamically stable with large binding energies of about 3.72 eV-6.86 eV. Interestingly, all the TM-intercalated graphene/MoS2 heterostructures are ferromagnetic and their total magnetic moments increase with TM concentration. Furthermore, TM concentration-dependent spin polarization is obtained for the graphene layer and MoS2 layer due to the charge transfer between TM atoms and the layers. A significant band gap is opened for graphene in these TM-intercalated graphene/MoS2 heterostructures (around 0.094 eV-0.37 eV). With the TM concentration increasing, the band gap of graphene is reduced due to the enhanced spin polarization of graphene. Our study suggests a research direction for the manipulation of the properties of 2D materials through control of the intercalation concentration of TM atoms.

| S-EPMC9864100 | biostudies-literature

First-principles study on the electronic and optical properties of Bi2WO6.

Project description:Photocatalytic materials attract continued scientific interest due to their possible application in energy harvesting. These applications critically rely on efficient photon absorption and exciton physics, which are governed by the underlying electronic structure. We report the electronic properties and optical response of the Bi2WO6 bulk photocatalyst using first-principle methods. The density functional theory DFT-computed electronic band gap is corrected by including Hubbard potentials for W-5d and O-2p orbitals, and one of the most advanced methods, Quasi-Particle (QP) GW at different levels, with semi-core states of Bi (5s and 5p) and W (4f), carefully taken into account in GW calculations. The perplexing nature of band character of Bi2WO6 is examined, and it comes out to be direct at PBE level without SOC. However, it shows indirect nature at GW level or when Spin-Orbit Coupling (SOC) is turned on even at PBE level. The optical response of the material system is computed within independent-particle approximation (IPA), taking into account local field effects and employing the time-dependent DFT (TDDFT) method. Bethe-Salpeter equation (BSE) is used to capture the excitonic effect, and the results of these approximations are compared with the experimental data. Our first-principle calculations results indicate that electron-hole interaction significantly modifies optical absorption of Bi2WO6, thereby verifying the reported experimental observations.

| S-EPMC9041973 | biostudies-literature

Insight into the electronic and thermodynamic properties of NbSi2 from first-principles calculations.

Project description:The electronic and thermodynamic properties of NbSi2 with four structures (C40, C11b, C54 and C49) were studied in terms of first-principle calculations. The band structure and density of states of four NbSi2 are calculated. Those disilicides show electronic properties because the band gap between the conduction band and the valence band is near the Fermi level. Their metallic character is mainly due to the strong metallic interaction between the Nb-4d state and Si-3p state. The formed Si-Si covalent bond is mainly concentrated in the valence band. The valence electron configuration of Nb-Si and Si-Si bonds is also explored. Besides, we study the thermodynamic properties of NbSi2 as a function of temperature. The results indicate that the C54 structure has the best thermal stability in the obtained phases. In particular, the Debye temperature and heat capacity of the C54 structure are 547.8 K and 142.7 J mol-1 K-1, respectively. The calculated phonon DOS provides the explanation that the nature of the thermodynamic properties is mainly derived from the vibration of Si atoms.

| S-EPMC9084393 | biostudies-literature

Electronic and Magnetic Properties of Lanthanum and Strontium Doped Bismuth Ferrite: A First-Principles Study.

Project description:While bismuth ferrite BiFeO3 (BFO) is a well studied multiferroic material, its electronic and magnetic properties in the presence of A-site dopants have not been explored widely. Here we report the results of a systematic study of the local electronic structure, spontaneous polarization, and magnetic properties of lanthanum (La) and strontium (Sr) doped rhombohedral bismuth ferrite within density functional theory. An enhanced ferroelectric polarization of 122.43 μC/cm2 is predicted in the uniformly doped BiLaFe2O6. We find that substitution of Sr in the A-site drives the system into a metallic state. The nature of magnetism arises mainly from the B-site Fe exhibiting a G-type antiferromagnetic ordering. Our study finds that upon dopant substitution, the local magnetic moment is decreased and its magnitude is dependent on the distance between the Fe and the dopant atom. The correlation between the local moment and the distance between the Fe and the dopant atom is discussed.

| S-EPMC6336767 | biostudies-literature

Electronic Transport Properties of Silicane Determined from First Principles.

Project description:Silicane, a hydrogenated monolayer of hexagonal silicon, is a candidate material for future complementary metal-oxide-semiconductor technology. We determined the phonon-limited mobility and the velocity-field characteristics for electrons and holes in silicane from first principles, relying on density functional theory. Transport calculations were performed using a full-band Monte Carlo scheme. Scattering rates were determined from interpolated electron-phonon matrix elements determined from density functional perturbation theory. We found that the main source of scattering for electrons and holes was the ZA phonons. Different cut-off wavelengths ranging from 0.58 nm to 16 nm were used to study the possible suppression of the out-of-plane acoustic (ZA) phonons. The low-field mobility of electrons (holes) was obtained as 5 (10) cm2/(Vs) with a long wavelength ZA phonon cut-off of 16 nm. We showed that higher electron (hole) mobilities of 24 (101) cm2/(Vs) can be achieved with a cut-off wavelength of 4 nm, while completely suppressing ZA phonons results in an even higher electron (hole) mobility of 53 (109) cm2/(Vs). Velocity-field characteristics showed velocity saturation at 3 × 105 V/cm, and negative differential mobility was observed at larger fields. The silicane mobility was competitive with other two-dimensional materials, such as transition-metal dichalcogenides or phosphorene, predicted using similar full-band Monte Carlo calculations. Therefore, silicon in its most extremely scaled form remains a competitive material for future nanoscale transistor technology, provided scattering with out-of-plane acoustic phonons could be suppressed.

| S-EPMC6766188 | biostudies-literature

First principles calculations of the structural, electronic, magnetic, and thermodynamic properties of the Nd2MgGe2 and Gd2MgGe2 intermetallic compounds.

Project description:In recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin-orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.

| S-EPMC8149671 | biostudies-literature

Insights into Structural, Electronic, and Transport Properties of Pentagonal PdSe2 Nanotubes Using First-Principles Calculations.

Project description:One-dimensional (1D) novel pentagonal materials have gained significant attention as a new class of materials with unique properties that could influence future technologies. In this report, we studied the structural, electronic, and transport properties of 1D pentagonal PdSe2 nanotubes (p-PdSe2 NTs). The stability and electronic properties of p-PdSe2 NTs with different tube sizes and under uniaxial strain were investigated using density functional theory (DFT). The studied structures showed an indirect-to-direct bandgap transition with slight variation in the bandgap as the tube diameter increased. Specifically, (5 × 5) p-PdSe2 NT, (6 × 6) p-PdSe2 NT, (7 × 7) p-PdSe2 NT, and (8 × 8) p-PdSe2 NT are indirect bandgap semiconductors, while (9 × 9) p-PdSe2 NT exhibits a direct bandgap. In addition, under low uniaxial strain, the surveyed structures were stable and maintained the pentagonal ring structure. The structures were fragmented under tensile strain of 24%, and compression of -18% for sample (5 × 5) and -20% for sample (9 × 9). The electronic band structure and bandgap were strongly affected by uniaxial strain. The evolution of the bandgap vs. the strain was linear. The bandgap of p-PdSe2 NT experienced an indirect-direct-indirect or a direct-indirect-direct transition when axial strain was applied. A deformability effect in the current modulation was observed when the bias voltage ranged from about 1.4 to 2.0 V or from -1.2 to -2.0 V. Calculation of the field effect I-V characteristic showed that the on/off ratio was large with bias potentials from 1.5 to 2.0 V. This ratio increased when the inside of the nanotube contained a dielectric. The results of this investigation provide a better understanding of p-PdSe2 NTs, and open up potential applications in next-generation electronic devices and electromechanical sensors.

| S-EPMC10254547 | biostudies-literature