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

摘要

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 (HD, (BB)-B-11-B-10 and (NN)-N-14-N-15) the nature of the most relevant modes related to the defects. The computed C-H stretching mode of CHN, once corrected for anharmonicity (3408cm which can then be reasonably attributed to this specific defect. The present manuscript is included in a special volume in honor and memory of Janos angyan. 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 Janos for the illuminating discussions they had in Paris, Nancy and Torino.