Abstract
PRB 75, 020509(R) (2007) We present a Raman scattering study of the E2g phonon anharmonicity and of
superconductivity induced self-energy effects in MgB2 single crystals. We show
that anharmonic two phonon decay is mainly responsible for the unusually large
linewidth of the E2g mode. We observe ~ 2.5 % hardening of the E2g phonon
frequency upon cooling into the superconducting state and estimate the
electron-phonon coupling strength associated with this renormalization.