Charge Ordering in Amorphous WO$_{x}$ Films

TL;DR

This study reveals a highly anisotropic, viscous electronic phase in amorphous WO$_{1.55}$ films, characterized by symmetry breaking and dynamic crystallization phenomena influenced by current, frequency, and temperature.

Contribution

It provides evidence for a dynamic Wigner crystal formation and stripe phases in amorphous WO$_{x}$ films, highlighting complex electronic behaviors in disordered systems.

Findings

Observation of anisotropic viscous electronic phase

Symmetry breaking leading to perpendicular metallic and insulating states

Evidence for dynamic Wigner crystal and stripe phases

Abstract

We report on the observation of highly anisotropic viscous electronic conducting phase in amorphous WO$_{1.55}$ 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 strongly suggest a dynamic crystallization of the disordered electronic matter, viz. formation of sliding Wigner crystal, as well as the occurrence of quantum smectic or stripe phase in the pinning-dominated regime.