Raman spectroscopy ofCa3Ru2O7: Phonon line assignment and electron scattering

M. N. Iliev, S. Jandl, V. N. Popov, A. P. Litvinchuk, J. Cmaidalka, R. L. Meng, J. Meen
2005 Physical Review B  
The polarized Raman spectra of layered ruthenate Ca 3 Ru 2 O 7 were measured between 5 and 300 K in several exact scattering configurations. All observed Raman lines were assigned to definite phonon modes of A 1 or A 2 symmetry on the basis of their polarization properties and by comparison to the results of lattice dynamical calculations for the orthorhombic A2 1 ma structure. It is established that the Fano-shaped A 2 mode, which exhibits a strong anomaly near the metal-nonmetal transition at
more » ... metal transition at T M = 48 K, involves mainly in-plane breathingtype oxygen vibrations. Other A 2 modes also exhibit detectable anomalies near T M . We argue that the phonon softening below T M is largely due to the orbital ordering and related structural changes.
doi:10.1103/physrevb.71.214305 fatcat:hlmeym52crccbbhherxbfkpome