Effect of long-range correlations on the Metal-Insulator Transitions in Vanadium Oxides*

The role of long-range electronic correlations in the metal-insulator (MIT) and structural phase (SPT) transitions in V$_{2}$O$_{3}$ and VO$_{2}$ are still under debate. In order to investigate the effect of disorder on the long-range correlations we irradiated V$_{2}$O$_{3}$ and VO$_{2}$ thin films with O$^{+}$ ion at different doses. We studied the effects on the transport and crystallographic properties as a function of the temperature across the phase transition. Both materials are sensitive to the irradiation, but effects on the transport and crystallographic properties across the phase transitions are different. We find changes in the transition temperature, lattice constant and magnitude of the MIT in both oxides. We interpreted this result as a change of the long-range order in vanadium oxides by ion irradiation. The response of VO$_{2}$ and V$_{2}$O$_{3}$ to the irradiation shed light on the SPT and MIT mechanisms.