  Joule-heating induced conductance-switching is studied in VO2, a Mott
insulator. Complementary in-situ techniques including optical characterization,
blackbody microscopy, scanning transmission x-ray microscopy (STXM) and
numerical simulations are used. Abrupt redistribution in local temperature is
shown to occur upon conductance-switching along with a structural phase
transition, at the same current.
