scholarly journals Stability and magnetic properties of isomorphous substituted Si7-xMnx+

2018 ◽  
Vol 56 (1) ◽  
pp. 64
Author(s):  
Nguyen Thanh Tung ◽  
Nguyen Thi Mai ◽  
Ngo Tuan Cuong

The optimized geometries, stability, and magnetic properties of cationic clusters Si7+, Si6Mn+, and Si5Mn2+ have been determined by the method of density functional theory using the B3P86/6-311+G(d) functional/basis set. Their electronic configurations have been analyzed to understand the influence of substituting Si atoms by Mn atoms on the structural and magnetic aspects of Si7+. It is shown that the manganese dopant does not alter the structure of the silicon host but significantly changes its stability and magnetism. In particular, while the magnetic moment of Si7+ is 1 mB, Si5Mn2+ exhibits a strong magnetic moment of 9 mB and that of Si6Mn+ takes a relatively high value of 4 mB. Among studied clusters, the pentagonal bipyramid Si5Mn2+ is assigned as the most stable one.


2017 ◽  
Vol 19 (23) ◽  
pp. 15021-15029 ◽  
Author(s):  
Yusheng Wang ◽  
Nahong Song ◽  
Min Jia ◽  
Dapeng Yang ◽  
Chikowore Panashe ◽  
...  

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).



2017 ◽  
Vol 31 (03) ◽  
pp. 1750017 ◽  
Author(s):  
Yan-Ni Wen ◽  
Peng-Fei Gao ◽  
Xi Chen ◽  
Ming-Gang Xia ◽  
Yang Zhang ◽  
...  

First-principles study based on density functional theory has been employed to investigate width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons (ZZ-MoS2 NRs). The width N = 4–6 (the numbers of zigzag Mo–S chains along the ribbon length) are considered. The results show that all studied ZZ-MoS2 NRs are less stable than two-dimensional MoS2 monolayer, exhibiting that a broader width ribbon behaves better structural stability and an inversely proportional relationship between the structural stability (or the ribbon with) and boundary S–Mo interaction. Electronic states imply that all ZZ-MoS2 NRs exhibit magnetic properties, regardless of their widths. Total magnetic moment increases with the increasing width N, which is mainly ascribed to the decreasing S–Mo interaction of the two zigzag edges. In order to confirm this reason, a uniaxial tension strain is applied to ZZ-MoS2 NRs. It has been found that, with the increasing tension strain, the bond length of boundary S–Mo increases, at the same time, the magnetic moment increases also. Our results suggest the rational applications of ZZ-MoS2 NRs in nanoelectronics and spintronics.



2019 ◽  
Vol 32 (2) ◽  
pp. 401-407
Author(s):  
M. Dinesh Kumar ◽  
P. Rajesh ◽  
R. Priya Dharsini ◽  
M. Ezhil Inban

The quantum chemical calculations of organic compounds viz. (E)-1-(2,6-bis(4-chlorophenyl)-3-ethylpiperidine-4-ylidene)-2-phenyl-hydrazine (3ECl), (E)-1-(2,6-bis(4-chlorophenyl)-3-methylpiperidine-4-ylidene)-2-phenylhydrazine (3MCl) and (E)-1-(2,6-bis(4-chloro-phenyl)-3,5-dimethylpiperidine-4-ylidene)-2-phenylhydrazine (3,5-DMCl) have been performed by density functional theory (DFT) using B3LYP method with 6-311G (d,p) basis set. The electronic properties such as Frontier orbital and band gap energies have been calculated using DFT. Global reactivity descriptor has been computed to predict chemical stability and reactivity of the molecule. The chemical reactivity sites of compounds were predicted by mapping molecular electrostatic potential (MEP) surface over optimized geometries and comparing these with MEP map generated over crystal structures. The charge distribution of molecules predict by using Mulliken atomic charges. The non-linear optical property was predicted and interpreted the dipole moment (μ), polarizability (α) and hyperpolarizability (β) by using density functional theory.



2008 ◽  
Vol 55-57 ◽  
pp. 857-860 ◽  
Author(s):  
Ekaphan Swatsitang ◽  
A. Pimsawat

ABINIT program package based on Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA) and plane wave basis set are used to calculate the magnetic properties of Mn doped NiO. It was found that the magnetic properties of Mn doped NiO were changed from anti-ferromagnetic (pure NiO) to ferromagnetism. Increasing the concentrations of Mn, the magnetization of Mn doped NiO were increased (Ni31MnO32 = 66.69 µB, Ni30Mn2O32 = 69.59 µB and Ni29Mn3O32 = 72.42 µB).



2012 ◽  
Vol 588-589 ◽  
pp. 51-54
Author(s):  
Lin Xu ◽  
Zong Lin Liu ◽  
Hong Kuan Yuan

The geometries, stabilities, electronic and magnetic properties of small GdnO3(n=1-5) clusters have been systematically studied by using density functional theory with the generalized gradient approximation. We found that the Gd atoms and O atoms in GdnO3clusters prefer three and two coordination, respectively, which origin from the electronic configurations of Gd and O atoms. The results show that Gd2O3cluster is more stable than its respective neighbors, which is reflected from its high average binding energy and high HOMO-LUMO gap. In addition, we calculate the magnetic properties of GdnO3clusters. The local magnetic moments of the Gd atom in the GdnO3clusters exhibit a weak dependence on the O atoms, which are slightly enhanced with the increasing of the number of Gd atom.



2016 ◽  
Vol 230 (5-7) ◽  
Author(s):  
Jonathan Guerrero-Sanchez ◽  
J. Castro-Medina ◽  
J. F. Rivas-Silva ◽  
Noboru Takeuchi ◽  
L. Morales de la Garza ◽  
...  

AbstractMn adsorption on the GaAs(111)–(1×1)B surface electronic and magnetic properties are investigated using first principles total energy calculations within the periodic spin polarized density functional theory. Results show that one Mn atom adsorption on top of the surface drives to an interstitial Mn atom. The interstitial atom is bonded to three first monolayer As atoms forming a chain-like structure. This stable structure has a ferromagnetic behavior with a Mn magnetic moment of ∼ 3.98 μ



2018 ◽  
Vol 127 (1A) ◽  
pp. 43
Author(s):  
Duong Tuan Quang

<p class="03Abstract">The density functional theory and time-dependent density functional theory methods were used for investigation of the excitation and emission properties of some fluorophores. The calculations were based on the optimized geometries of ground states and excited states at the B3LYP functional and LanL2DZ basis set. The results clarified the nature of the optical properties of the compounds and agreed well with the experimental data. The approximate values of excitation energies and emission energies of compounds were also identified. The calculated excitation energies were about 0.01 to 0.56 eV higher than experimental values. Meanwhile, the emission energies were from 0.34 to 0.89 eV higher than experimental values. These large errors occurred when there were great variations between the optimized geometries of ground state and excited states. They could be due to the presence of components of solvent in real solution that stabilized the excited states, leading to reduce the excitation and emission energies in the experiments.</p>



2011 ◽  
Vol 1298 ◽  
Author(s):  
Eugene Heifets ◽  
Denis Gryaznov

ABSTRACTWe have performed a detailed analysis of the magnetic (collinear and noncollinear) order and atomic and electron structures of UO2, PuO2 and UN on the basis of density functional theory with the Hubbard electron correlation correction (DFT+U). We have shown that the 3-k magnetic structure of UO2 is stabilized for the Hubbard parameter value of U=4.6 eV (while J=0.5 eV) when Dudarev’s formalism is used. UO2 keeps cubic shape in this structure. Two O atoms nearest to each U atom in direction of its magnetic moment move toward this U atom. Neither UN nor PuO2 shows the energetical preference for the rhombohedral distortion, in contrast to UO2, and, thus, no complex 3-k magnetic structure in these materials. Both materials have the AFM tetragonal <001> structure at reasonable choice of parameters U and J.



2016 ◽  
Vol 3 (1) ◽  
pp. 89 ◽  
Author(s):  
Shalika Ram Bhandari ◽  
Ram Kumar Thapa ◽  
Madhav Prasad Ghimire

<p>Electronic and magnetic properties of La<sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub> had been studied by first-principles density functional theory (DFT). Based on the DFT calculation La<sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub> is found to have a ferromagnetic (FM) ground state. The material undergo charge-transfer type insulator to Mott-Hubbard type insulator transition which happens due to strong correlation in La-4f and Cu-3d states. Our results show that the 3d electrons of Cu hybridize strongly with O-2p states near the Fermi level giving rise to the insulating state of La<sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub>. Our study suggests that the enhanced magnetic moment is a result of itinerant exchange rather than the exchange interaction involving individual ions of Cu atoms. The total magnetic moment calculated in the present studies is 2 μ<sub>B</sub> per unit cell for La<sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub>.</p><p>Journal of Nepal Physical Society Vol.3(1) 2015: 89-96</p>



SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950015
Author(s):  
Sikander Azam ◽  
Mamoona Mahboob ◽  
Sobia Ali ◽  
Malika Rani ◽  
Muhammad Irfan ◽  
...  

We are attempting to study the properties of new materials based on Diamond-like semiconductors (DLS). Due to broad collection of useful properties, DLS are exciting materials to study. The novel substances Li2MnGeS4 and Li2CoSnS4 result from using a rational and guileless design approach that leads the discovery of DLSs with wide-ranging regions of optical transparency. So here, we have analyzed their applications in atomic devices and system called “optoelectronic” using the FP-APW method and mBJ method. The band gap value for Li2MnGeS4 is 2.911[Formula: see text]eV and Li2CoSnS4 is 2.45[Formula: see text]eV. The present DLS materials confirm their semiconductor characters. The presence of iron and manganese in these compounds have generated magnetic properties that we explored by the calculation of magnetic moment and spin-densities maps.



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