Electrical half-wave rectification at ferroelectric domain walls

TL;DR

This paper demonstrates that neutral 180° ferroelectric domain walls in ErMnO₃ can act as 2D half-wave rectifiers, enabling AC to DC conversion at the nanoscale with potential for novel nanoelectronic devices.

Contribution

It introduces the concept of domain walls functioning as half-wave rectifiers, combining experimental and theoretical analysis to reveal their rectification capabilities.

Findings

Domain walls exhibit diode-like AC to DC conversion.

Rectification occurs at frequencies where domain walls are fixed.

Oxygen defect accumulation explains transport behavior.

Abstract

Ferroelectric domain walls represent multifunctional 2D-elements with great potential for novel device paradigms at the nanoscale. Improper ferroelectrics display particularly promising types of domain walls, which, due to their unique robustness, are the ideal template for imposing specific electronic behavior. Chemical doping, for instance, induces p- or n-type characteristics and electric fields reversibly switch between resistive and conductive domain-wall states. Here, we demonstrate diode-like conversion of alternating-current (AC) into direct-current (DC) output based on neutral 180$^{\circ}$ domain walls in improper ferroelectric ErMnO$_3$. By combining scanning probe and dielectric spectroscopy, we show that the rectification occurs for frequencies at which the domain walls are fixed to their equilibrium position. The practical frequency regime and magnitude of the output is controlled by the bulk conductivity. Using density functional theory we attribute the transport behavior at the neutral walls to an accumulation of oxygen defects. Our study reveals domain walls acting as 2D half-wave rectifiers, extending domain-wall-based nanoelectronic applications into the realm of AC technology.