  Metal-insulator transitions (MIT) belong to a class of fascinating physical
phenomena, which includes superconductivity, and colossal magnetoresistance
(CMR), that are associated with drastic modifications of electrical resistance.
In transition metal compounds, MIT are often related to the presence of strong
electronic correlations that drive the system into a Mott insulator state. In
these systems the MIT is usually tuned by electron doping or by applying an
external pressure. However, it was noted recently that a Mott insulator should
also be sensitive to other external perturbations such as an electric field. We
report here the first experimental evidence of a non-volatile
electric-pulse-induced insulator-to-metal transition and possible
superconductivity in the Mott insulator GaTa4Se8. Our Scanning Tunneling
Microscopy experiments show that this unconventional response of the system to
short electric pulses arises from a nanometer scale Electronic Phase Separation
(EPS) generated in the bulk material.
