Temperature-dependent phonon lifetime of the 428-cm-1 Raman line in La2CuO4+y

Raman measurements of the 428-cm-1 A1g oxygen vibrational mode in single-crystal La2CuO4+y show that the linewidth of this dominant line increases by a factor of 2 from 8 to 300 K, while its line position varies by less than 1 cm-1 over this temperature range. The variation with temperature of the linewidth of the zone-center optical phonon of frequency ω0 is well explained by a three-phonon scattering process involving a decay to two phonons with wave vectors k and -k and frequencies near ω0/2. No changes in either the linewidth or the line position was observed upon application of a magnetic field (H parallel z) up to 11 T