Inelastic (Raman) scattering provides a powerful means to probe simultaneously spin, charge, and lattice dynamics in strongly correlated electron systems. Ca2-xSrxRuO4 (CSRO) exhibits a rich phase diagram due to strongly correlated magnetic, electronic, and phononic degrees of freedom. We present Raman scattering results of the CSRO system as functions of temperature and Sr substitution. Raman scattering spectra from Ca2RuO4 reveal (1) a two-magnon (2M) scattering response at 102 cm-1 in the antiferromagnetic (AF) phase regime, (2) an increase of the electron-phonon interaction strength with increasing temperature through the AF ordering temperature (TN ~ 113 K) well below the metal-insulator transition temperature (TMI ~ 357 K), and (3) a significant renormalization of the phonon energy and linewidth above TN. The 2M energy at T = 10 K is relatively insensitive to Sr substitution. In contrast, Sr substitution causes a much more dramatic renormalization of the 2M energy and linewidth with increasing temperature toward TN. Moreover, Raman scattering spectra show that Sr substitution results in a significant increase in the electron-phonon interaction strength. Interestingly, Raman scattering from CSRO for 0 < x ￡ 0.2 shows a charge gap development near 600 cm-1 in the AF insulating state. With increasing temperature, unlike the other correlation gap materials, the charge gap closes well below TMI, suggesting coexistence of insulating and metallic components for T< TMI.
