Charge ordering in amorphous WOx films

Abstract

We report on the observation of highly anisotropic viscous electronic conducting phase in amorphous WO1.55 films that occurs below a current (I)- and frequency (f)-dependent temperature T* (I, f). At T < T*(I, f) the rotational symmetry of randomly disordered electronic background is broken leading to the appearance of mutually perpendicular metallic- and insulating-like states. A rich dynamic behavior of the electronic matter occurring at T < T* (I, f) provides evidence for an interplay between pinning effects and electron-electron interactions. The results suggest a dynamic crystallization of the disordered electronic matter, viz. formation of sliding Wigner crystal, as well as the occurrence of quantum liquid-like crystal or stripe phase at low drives. (c) 2007 Elsevier B.V. All rights reserved.