Current‐driven switching of a small‐polaron semiconductor to a meta‐stable conductor

Abstract Many materials with low‐mobility charge carriers manifest current‐driven electronic switching between low‐conductivity and high‐conductivity transport. Available measurements suggest that the low‐conductivity carriers of these switches form small polarons. Here a mechanism is described via which driving a sufficiently high current through a material whose carriers form small polarons destabilizes them with respect to forming free carriers. The electrical conductivity then rises sharply since a free‐carrier's mobility is many orders of magnitude higher than that of a small polaron. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)