Low-temperature Raman spectra of YbVO4

This paper reports on the spectroscopic study of YbVO4 in the range 10–300 K. All the Raman phonons were properly assigned. Temperature-dependent Raman spectra showed no anomalous changes, which indicate that neither structural phase transition nor strong electron–phonon coupling occur, at least within this temperature range. This result is sharp contrast to those of YbPO4 where strong mixing of the upper crystal-field states Γ6 and Γ7 with an Eg3 phonon at room–temperature occurs. A possible explanation for the absence of electron-phonon coupling in YbVO4 is the occurrence of the Γ6 state at energy higher than the Eg3 phonon, unlike the coincidence of Γ6 and Eg3 energies in YbPO4.