Raman spectroscopy and phonon dynamics in strained V2O3

Transition metal oxides are known to have a strong interplay of many degrees of freedom giving rise to their rich phase diagrams with competing ground states. The Mott material ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ hosting a room- and low-temperature metal-insulator transition is a great example where electronic, structural and magnetic ordering are the directors at play. By combining first-principle calculations and Raman spectroscopy, we study the phonon dynamics of ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ to gain further understanding in the interplay of these ordering mechanisms driving the transitions. First-principle calculations show that the Raman active vibrations correspond to the structural distortions occurring in the phase diagram. Additionally, Raman spectroscopy is performed on a unique series of epitaxial strained $1.5%$ Cr-doped ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ thin films, where both paramagnetic insulating, metallic, as well as intermediate electronic states are stabilized. This has led to identifying the importance of the local V-V dimer elongation that drives both the room- and low-temperature MIT in ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ compounds.