Switching voltage of first-order metal-insulator transition (MIT) in VO_2, an inhomogeneous strongly correlated system, is changed by irradiating an infrared light with wavelength, 1.5 micrometer, and applying the electric field (photo-induced switch
ing). This was predicted in the hole-driven MIT theory in which hole doping of a low concentration below 0.01% into conduction band (Fermi surface) induces the abrupt MIT as correlation effect. The switching is explained by the Mott transition not the Peierls transition.
