Ferroelectric domain walls for environmental sensors

TL;DR

This paper demonstrates that ferroelectric domain walls in Er(Mn,Ti)O$_3$ can reversibly change their electronic conduction in response to environmental oxygen levels, enabling new nanoelectronic environmental sensors.

Contribution

It introduces a novel concept of using ferroelectric domain walls as reversible, environment-sensitive electronic components for sensor technology.

Findings

Domain walls switch between insulating and conducting states under different atmospheres.

Charge carrier density modulations caused by oxygen interstitials explain the conduction changes.

The work proposes a new application of domain walls in environmental sensing.

Abstract

Domain walls in ferroelectric oxides provide fertile ground for the development of next-generation nanotechnology. Examples include domain-wall-based memory, memristors, and diodes, where the unusual electronic properties and the quasi-2D nature of the walls are leveraged to emulate the behavior of electronic components at ultra-small length scales. Here, we demonstrate atmosphere-related reversible changes in the electronic conduction at neutral ferroelectric domain walls in Er(Mn,Ti)O$_3$. By exposing the system to reducing and oxidizing conditions, we drive the domain walls from insulating to conducting, and vice versa, translating the environmental changes into current signals. Density functional theory calculations show that the effect is predominately caused by charge carrier density modulations, which arise as oxygen interstitials accumulate at the domain walls. The work introduces an innovative concept for domain-wall based environmental sensors, giving an additional dimension to the field of domain wall nanoelectronics and sensor technology in general.