Spectroscopic and first-principles studies of boron-doped diamond: Raman polarizability and local vibrational bands

Using the first-principles study within the local-density approximation, the projector augmented wave method and plane-wave basis, calculating the Hellmann–Feynman forces and applying the direct method for lattice-dynamical analysis, the relaxation of the structures and partial density of phonon states in boron-doped diamond crystals of BC7, BC31, BC63 and BC215 were obtained. It is found that lattice parameters, as well as the B–C and C–C bondlengths, increase with doping, at that the B–C bond is longer than the C–C bond even in the BC215 crystal with smaller concentration of boron (0.46%). The comparison of partial densities of phonon states for boron and carbon atoms, as well as for carbon in undoped diamond, shows that localized vibrations of boron atoms contributes to the density of phonon states and Raman spectra of B-doped diamond.