scholarly journals Spin Polarization and Magnetic Moment in Silicon Carbide Grown by the Method of Coordinated Substitution of Atoms

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5579
Author(s):  
Sergey A. Kukushkin ◽  
Andrey V. Osipov

In the present work, a new method for obtaining silicon carbide of the cubic polytype 3C-SiC with silicon vacancies in a stable state is proposed theoretically and implemented experimentally. The idea of the method is that the silicon vacancies are first created by high-temperature annealing in a silicon substrate Si(111) doped with boron B, and only then is this silicon converted into 3C-SiC(111), due to a chemical reaction with carbon monoxide CO. A part of the silicon vacancies that have bypassed “chemical selection” during this transformation get into the SiC. As the process of SiC synthesis proceeds at temperatures of ~1350 °C, thermal fluctuations in the SiC force the carbon atom C adjacent to the vacancy to jump to its place. In this case, an almost flat cluster of four C atoms and an additional void right under it are formed. This stable state of the vacancy, by analogy with NV centers in diamond, is designated as a C4V center. The C4V centers in the grown 3C-SiC were detected experimentally by Raman spectroscopy and spectroscopic ellipsometry. Calculations performed by methods of density-functional theory have revealed that the C4V centers have a magnetic moment equal to the Bohr magneton μB and lead to spin polarization in the SiC if the concentration of C4V centers is sufficiently high.

2010 ◽  
Vol 21 (12) ◽  
pp. 1469-1477 ◽  
Author(s):  
M. SAMAH ◽  
B. BOUGHIDEN

Structures, binding energies, magnetic and electronic properties endohedrally doped C 20 fullerenes by metallic atoms ( Fe , Co , Ti and V ) have been obtained by pseudopotential density functional theory. All M @ C 20, except Co @ C 20, are more stable than the undoped C 20 cage. The magnetic moment values are 1 and 2μB. These values and semiconductor behavior give to these compounds interesting feature in several technological applications. Titanium doped C 20 has a same magnetic moment than the isolated Ti atom. Hybridization process in the Co doped C 20 fullerene is most strong than in other doped cages. Electrical and magnetic dipoles calculated in the iron doped C 20 are very strong compared with other clusters.


Author(s):  
Nadezda A. Borshch ◽  
Sergey I. Kurganskii

Представлены результаты моделирования пространственной структуры и электронных свойств кластеров MeGe16 - и MeGe20 - (Me = Sc, Y, Lu). Рассматривается возможность синтеза  пуллереноподобных кластеров и кластеров с другими типами замкнутых структур. Проведены сравнительные расчеты в рамках теории функционала плотности с использованием базиса SDD и трех различных потенциалов – B3LYP, B3PW91 и PBEPBE. Анализируется влияние выбора потенциала на результаты моделирования пространственной структуры кластеров и их электронного спектра. Оценка адекватности теоретических методов проводится путем сравнения рассчитанных электронных спектров с экспериментальными результатами по фотоэлектронной спектроскопии кластеров.     REFERENCES Kroto H. W., Heath J. R., O’Brien S. C., Curl R. F., Smalley R. E. C60: Buckminsterfullerene. Nature, 1985, v. 318, pp. 162-163. https://doi.org/10.1038/318162a0 Hiura H., Miyazaki, Kanayama T. Formation of Metal-Encapsulating Si Cage Clusters. Phys. Rev. Lett., 2001, v. 86, p. 1733. https://doi.org/10.1103/PhysRev-Lett.86.1733 Wang J., Han J. Geometries, stabilities, and electronic properties of different-sized ZrSin (n=1–16) clusters: A density-functional investigation. Chem. Phys., 2005, v. 123(6), pp. 064306–064321. https://doi.org/10.1063/1.1998887 Guo L.-J., Liu X., Zhao G.-F. Computational investigation of TiSin (n=2–15) clusters by the densityfunctional theory. Chem. Phys., 2007, v. 126(23), pp. 234704–234710.  https://doi.org/10.1063/1.2743412 Li J., Wang G., Yao C., Mu Y., Wan J., Han M. Structures and magnetic properties of SinMn (n=1–15) clusters. Chem. Phys., 2009, v. 130(16), pp. 164514–164522.  https://doi.org/10.1063/1.3123805 Borshch N. A., Berestnev K. S., Pereslavtseva N. S., Kurganskii S. I. Geometric structure and electron spectrum of YSi n− clusters (n = 6–17) Physics of the Solid State, 2014, v. 56(6), pp. 1276–1281. https://doi.org/10.1134/S1063783414060080 Borshch N., Kurganskii S. Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6–20). Appl. Phys., 2014, v. 116(12), pp. 124302-1 – 124302-8. https://doi.org/10.1063/1.4896528 Borshch N. A., Pereslavtseva N. S., Kurganskii S. I. Spatial structure and electronic spectrum of TiSi n - Clusters (n = 6–18). Russian Journal of Physical Chemistry A, v. 88(10), pp. 1712–1718. https://doi.org/10.1134/S0036024414100070 Borshch N. A., Pereslavtseva N. S., Kurganskii S. I. Spatial and electronic structures of the germanium-tantalum clusters TaGe n − (n = 8–17). Physics of the Solid State, 2014, vol. 56(11), pp. 2336–2342. https://doi.org/10.1134/S1063783414110055 Huang X., Yang J. Probing structure, thermochemistry, electron affi nity, and magnetic moment of thulium-doped silicon clusters TmSi n (n = 3–10) and their anions with density functional theory. Mol. Model., 2018, v. 24(1), p. 29. https://doi.org/10.1007/s00894-017-3566-7 Zhang, Y., Yang, J., Cheng, L. J. Probing Structure, Thermochemistry, Electron Affi nity and Magnetic Moment of Erbium-Doped Silicon Clusters ErSin (n = 3–10) and Their Anions with Density Functional Theory. Sci., 2018, v. 29(2), pp. 301–311. https://doi.org/10.1007/s10876-018-1336-z Ye T., Luo C., Xu B., Zhang S., Song H., Li G. Probing the geometries and electronic properties of charged Zr2Si n q (n = 1–12, q = ±1) clusters. Chem., 2018, v. 29(1), pp. 139–146.  https://doi.org/10.1007/s11224-17-1011-2 Nguyen M.T., Tran Q. T., Tran V.T. A CASSCF/ CASPT2 investigation on electron detachments from ScSi n − (n = 4–6) clusters. Mol. Model., 2017, v. 23(10), p. 282. https://doi.org/10.1007/s00894-017-3461-2 Liu Y., Jucai Yang J., Cheng L. Structural Stability and Evolution of Scandium-Doped Silicon Clusters: Evolution of Linked to Encapsulated Structures and Its Infl uence on the Prediction of Electron Affi nities for ScSin (n = 4–16) Clusters. Chem., 2018, v. 57(20), pp 12934–12940. https://doi.org/10.1021/acs.inorgchem.8b02159


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 (3) ◽  
pp. 1896-1908 ◽  
Author(s):  
H. Tavassoli Larijani ◽  
M. Jahanshahi ◽  
M. Darvish Ganji ◽  
M. H. Kiani

In the present work, the adsorption of glycine amino acid and its zwitterionic form onto three different hexagonal sheets, namely graphene, boron-nitride (h-BN) and silicon carbide (h-SiC), has been investigated within the framework of density functional theory (DFT) calculations.


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.


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