Optical study of the Mott transition in V 2 O 3 : Comparison of time- and frequency-domain results

We report the results of an optical study of the Mott transition in ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ carried out by time- and frequency-domain spectroscopies. We have observed time-resolved spectra through the Mott transition with oscillations in reflectivity associated with the fully symmetric modes. As a consequence of the phase transition, the Raman spectrum also shows an abrupt change of both the phonon and electronic excitations. Most notable are (i) disappearance of the electronic continuum, which is very strong and broad in the metallic state, and (ii) altered coupling of a fully symmetric phonon to the electronic subsystem, which is shown to be temperature dependent even above the transition. We notice that although the spectra obtained by the time- and frequency-domain spectroscopies are similar, there are distinct differences in phonon line shape.