Linear response calculation of first‐order Raman spectra of point defects in silicon carbide

Roma, Guido

doi:10.1002/pssa.201600036

Cited by 17 publications

(11 citation statements)

References 36 publications

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“…This is why we believe that the new peak of the Raman spectrum at 952 cm −1 ( Figure 6 ) is associated with the vibrations of the C-C bonds. A similar line was also found in the DFT calculations in the 3C-SiC containing carbon antisites [ 26 ]. Because of the described overjump, an additional void with a diameter of 1.85 Å appears under the carbon cluster at a distance of 2.0 Å.…”

Section: Modeling Of the Magnetic And Electrical Properties Of 3c-sic Produced By The Methods Of Coordinated Substitution Of Atoms (Mcsa)supporting

confidence: 86%

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

Кукушкин¹,

Осипов²

2021

Materials

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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.

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Section: Modeling Of the Magnetic And Electrical Properties Of 3c-sic Produced By The Methods Of Coordinated Substitution Of Atoms (Mcsa)supporting

confidence: 86%

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

Кукушкин¹,

Осипов²

2021

Materials

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“…This, nonetheless, poses a substantial challenge with regards to the accuracy of calculations of vibrational properties. Although Raman spectra can be accurately calculated in the intramolecular region (wavenumbers > 150 cm –1 ), − good agreement between theory and experiment in the low-wavenumber region has so far proved elusive. Quasi-harmonic lattice dynamics calculations based on force field potentials (FFPs) have been shown to be in qualitative agreement with experimental data (to within 20 cm –1 ) .…”

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confidence: 99%

DFT-Assisted Polymorph Identification from Lattice Raman Fingerprinting

Bedoya-Martínez

Schrode

Jones

et al. 2017

J. Phys. Chem. Lett.

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A combined experimental and theoretical approach, consisting of lattice phonon Raman spectroscopy and density functional theory (DFT) calculations, is proposed as a tool for lattice dynamics characterization and polymorph phase identification. To illustrate the reliability of the method, the lattice phonon Raman spectra of two polymorphs of the molecule 2,7-dioctyloxy[1]benzothieno[3,2-b]benzothiophene are investigated. We show that DFT calculations of the lattice vibrations based on the known crystal structures, including many-body dispersion van der Waals (MBD-vdW) corrections, predict experimental data within an accuracy of ≪5 cm–1 (≪0.6 meV). Due to the high accuracy of the simulations, they can be used to unambiguously identify different polymorphs and to characterize the nature of the lattice vibrations and their relationship to the structural properties. More generally, this work implies that DFT-MBD-vdW is a promising method to describe also other physical properties that depend on lattice dynamics like charge transport.

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“…Radiation defects with charged states in SiC may also affect the Raman spectra. The knowledge regarding this effect is currently limited …”

Section: Discussionmentioning

confidence: 99%

Raman spectroscopy of neutron irradiated silicon carbide: Correlation among Raman spectra, swelling, and irradiation temperature

Koyanagi

Katoh

Lance

2018

J Raman Spectroscopy

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The effects of neutron irradiation on microstructural evolution and the resultant changes in physical and mechanical properties are of critical importance for the development of silicon carbide (SiC) materials for nuclear applications. This study neutron-irradiated β-SiC under a wide range of conditions at temperatures between 235 and 750°C and neutron doses of 0.01-11.8 displacements per atom, and then evaluated the effects on the SiC structure using Raman spectroscopy. The SiC optical phonon lines were shifted to

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Linear response calculation of first‐order Raman spectra of point defects in silicon carbide

Cited by 17 publications

References 36 publications

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

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

DFT-Assisted Polymorph Identification from Lattice Raman Fingerprinting

Raman spectroscopy of neutron irradiated silicon carbide: Correlation among Raman spectra, swelling, and irradiation temperature

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