Lattice dynamics and the electron-phonon interaction in Ca$_2$RuO$_4$

H. Rho; S. L. Cooper; S. Nakatsuji; H. Fukazawa; Y. Maeno

doi:10.1103/PhysRevB.71.245121

paper

Lattice dynamics and the electron-phonon interaction in Ca $_{2}$ RuO $_{4}$

arXiv:cond-mat/0501620 · doi:10.1103/PhysRevB.71.245121

Abstract

We present a Raman scattering study of Ca $_{2}$ RuO $_{4}$ , in which we investigate the temperature-dependence of the lattice dynamics and the electron-phonon interaction below the metal-insulator transition temperature ({\it T} $_{MI}$ ). Raman spectra obtained in a backscattering geometry with light polarized in the ab-plane reveal 9 B $_{1 g}$ phonon modes (140, 215, 265, 269, 292, 388, 459, 534, and 683 cm $^{- 1}$ ) and 9 A $_{g}$ phonon modes (126, 192, 204, 251, 304, 322, 356, 395, and 607 cm $^{- 1}$ ) for the orthorhombic crystal structure (Pbca $-$ D $_{2 h}^{15}$ ). With increasing temperature toward {\it T} $_{MI}$ , the observed phonon modes shift to lower energies and exhibit reduced spectral weights, reflecting structural changes associated with the elongation of the RuO $_{6}$ octahedra. Interestingly, the phonons exhibit significant increases in linewidths and asymmetries for {\it T} $>$ {\it T} $_{N}$ . These results indicate that there is an increase in the effective number of electrons and the electron-phonon interaction strengths as the temperature is raised through {\it T} $_{N}$ , suggesting the presence of orbital fluctuations in the temperature regime {\it T} $_{N}$ $<$ {\it T} $<$ {\it T} $_{MI}$ .

6 pages, 4 figures

Lattice dynamics and the electron-phonon interaction in Ca $_{2}$ RuO $_{4}$

Abstract

References in corpus (8)

Cited by in corpus (12)

Lattice dynamics and the electron-phonon interaction in Ca2​RuO4​

Abstract

References in corpus (8)

Cited by in corpus (12)

Lattice dynamics and the electron-phonon interaction in Ca $_{2}$ RuO $_{4}$