Hydrogen, boron and nitrogen atoms in diamond: a quantum mechanical vibrational analysis

Abstract

The structural, electronic and vibrational properties of two common defects in diamond, CHN and CHB, describing the case in which a carbon C 1 atom is substituted by a nitrogen atom, or by a boron atom, breaking a C 1-C 2 bond, followed by the saturation of the dangling bond of C 2 by a hydrogen atom, are investigated at the quantum mechanical level, by using a periodic supercell approach, hybrid DFT functionals and a local Gaussian-type basis set as implemented in the CRYSTAL code. The effect of concentration of the defects has been explored, by considering two supercells containing 64 and 216 atoms (S 64 and S 216). Formation and hydrogenation energies, geometries, Mulliken charges and the band structure of both defects are reported. The vibrational features of the defects have been investigated, by generating the IR and Raman spectra, and by analyzing graphically and through the isotopic substitution (H → D, 11 B → 10 B and 14 N → 15 N) the nature of the most relevant modes related to the defects. The computed C-H stretching mode of CHN, once corrected for anharmonicity (3408 cm −1), falls to wavenumbers very close to the experimental peak observed at 3394 cm −1 , which can then be reasonably attributed to this specific defect. The present manuscript is included in a special volume in honor and memory of János Ángyán. Although he did not study in particular the kind of defects discussed in the present manuscript, the many methodological contributions he introduced in computational science have inspired many of the tools we have been using here. One of the present authors, RD, in particular, is grateful to János for the illuminating discussions they had in Paris, Nancy and Torino.

Hunting the elusive shallow n-type donor – An ab initio study of Li and N co-doped diamond

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Vibrational Analysis of Paraelectric–Ferroelectric Transition of LiNbO3: An Ab-Initio Quantum Mechanical Treatment

“…As shown by a previous paper, the combined use of the B3LYP functional and the triple ζ basis set [20][21][22][23][24][25][26] provides very accurate results for the vibrational spectra, in terms of both wavenumbers and intensities [25,[27][28][29][30][31]. The exchange and Coulomb infinite lattice series can be modified through five parameters, T i , which were set to 8 (T 1 -T 4 ) and 16 (T 5 ).…”

On the Models for the Investigation of Charged Defects in Solids: The Case of the VN– Defect in Diamond

“…This scheme is already well tested in previous works about diamond structures involving vacancy defects and nitrogen substitutions. [20][21][22][23][24] For the P atom a large core pseudopotential has been adopted so that only the five valence electrons are explicitly considered. 25 The truncation criteria of the Coulomb and exchange infinite lattice series are controlled by five thresholds, T i , which have been set to 8 (T 1 -T 4 ) and 16 (T 5 ).…”