Quasi-one-dimensional metallic conduction channels in exotic ferroelectric topological defects

TL;DR

This paper demonstrates the existence of reversible, high-conductance quasi-one-dimensional metallic channels along exotic ferroelectric topological defects in BiFeO3 nanoislands, with potential applications in nanoelectronics and nonvolatile memory.

Contribution

It reveals the formation and control of metallic conduction channels along topological defects in ferroelectric materials, a novel approach for nanoelectronic device design.

Findings

Metallic channels are confined to topological cores in BiFeO3 nanoislands.

Channels can be created, manipulated, and erased using electric fields.

Electroresistance ratio exceeds 10^3, enabling memory applications.

Abstract

Ferroelectric topological objects (e.g. vortices, skyrmions) provide a fertile ground for exploring emerging physical properties that could potentially be utilized in future configurable nanoelectronic devices. Here, we demonstrate quasi-one-dimensional metallic high conduction channels along two types of exotic topological defects, i.e. the topological cores of (i) a quadrant vortex domain structure and (ii) a center domain (monopole-like) structure confined in high quality BiFeO3 nanoisland array, abbreviated as the vortex core and the center core. We unveil via phase-field simulations that the superfine (< 3 nm) metallic conduction channels along center cores arise from the screening charge carriers confined at the core whereas the high conductance of vortex cores results from a field-induced twisted state. These conducting channels can be repeatedly and reversibly created and deleted by manipulating the two topological states via an electric field, leading to an apparent electroresistance effect with an on/off ratio higher than 103. These results open up the possibility of utilizing these functional one-dimensional topological objects in high-density nanoelectronic devices such as ultrahigh density nonvolatile memory.