Supra-Binary Ferroelectricity in a Nanowire

TL;DR

This paper predicts and observes supra-binary ferroelectricity in a nanowire, revealing multiple polarization states driven by gate voltage, which could enable multi-bit data manipulation in ferroelectric devices.

Contribution

It introduces a novel ferroelectric phase in nanowires with multiple polarization states controlled by anisotropic electric fields, distinct from traditional binary ferroelectricity.

Findings

Identification of four polarization phases in ferroelectric nanowires.

Observation of gate-voltage-driven transitions between these phases.

Potential for multi-bit information manipulation in ferroelectric devices.

Abstract

We report the prediction and observation of supra-binary ferroelectricity in a ferroelectric nanowire (FNW) covered with a semi-cylindrical gate that provides an anisotropic electric field in the FNW. There are gate-voltage-driven transitions between four polarization phases in FNW's cross section, dubbed axial-up, axial-down, radial-in and radial-out. They are determined by the interplay between the topological depolarization energy and the free energy induced by an anisotropic external electric field, in clear distinction from the conventional film-based binary ferroelectricity. When the FNW is mounted on a biased graphene nanoribbon (GNR), these transitions induce exotic current-voltage hysteresis in the FNW-GNR transistor. Our discovery suggests new operating mechanisms of ferroelectric devices. In particular, it enables intrinsic multi-bit information manipulation in parallel to the binary manipulation employed in data storage devices.