An investigation of phonon decay in B₁₂ As₂ by Raman scattering spectroscopy

Raman scattering spectroscopy was used to study the spectral linewidth and frequency of characteristic phonon modes of boron arsenide (B12 As2) as a function of temperature between 7 and 680 K. A combination of two- and three-phonon decay processes was found to dominate the dynamics of the intra-icosahedral phonon modes at 624, 682, and 742 cm-1, whilst two-phonon decay appears to be favored for the As-As stretch mode at 310 cm-1 and for the 506 cm-1 mode. Changes in frequency with temperature predominantly contain contributions from lattice expansion for all modes except the 506 cm-1 Eg mode, where contributions from phonon damping play a more significant role.