Electrical Switching Phenomena in Transition Metal Glasses under the Influence of High Electric Fields

Abstract A mechanism is proposed to account for the phenomena observed in many vitreous systems of field‐induced switching between two or more conducting states. Conduction in the high resistance state is assumed to involve electron hopping between non‐identical sites. The vitreous nature of the systems precludes extrinsic conduction, and the equilibrium number of intrinsic carriers is shown to be a function of the degree of inequality of site configurations, temperature, field strength, and dielectric constant. The carrier mobility is a function of averaged distance between sites, of temperature, and dielectric constant. Dc conduction and dipole production and orientation are shown to be interrelated processes. The consequent non‐linear dependence of polarization on field leads to a quasi‐ferroelectric reorganization of the structure at a critical field strength. The structural reorganization makes the site environments more nearly identical, and thereby delocalizes the excess electrons on one of the sites producing semi‐metallic conduction. Local energy dissipation by the turn‐off pulse raises the lattice temperature sufficiently to allow the structure to relax to its initial state. The quantitative implications of the theory are developed, and compared with measurements on some copper glasses.