Resonance Raman and quasi-particle dynamics investigated in underdoped Bi2212 Original Research Article

In this work, we present Raman scattering study of anomalous features and magnetic excitations in underdoped Bi2212. We carried out systematic resonance Raman study and observed resonance profiles for different vibrational and electronic excitations. We clarified the origin of the anomalous feature at 600 cm−1 excitations. We have extended our study to investigate quasi-particle dynamics and elementary excitations by picosecond Raman spectroscopy. We observed super-linear behaviour in the power dependence of the anti-Stokes side in contrast to the Stokes side. As for magnetic excitations we also observed non-linear behaviour in the power dependence of the two-magnon peak. We propose to understand the non-linear behaviour in terms of non-equilibrium phonons and excess magnon population.