Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO$_3$

TL;DR

This study investigates how Ti$^{4+}$ B-site doping in hexagonal ErMnO$_3$ influences electronic properties and domain wall conduction, revealing intrinsic domain wall currents and Poole-Frenkel conductance as a key mechanism.

Contribution

It provides new insights into the effects of B-site doping on electronic response and domain wall behavior in hexagonal manganites, an area previously underexplored.

Findings

Ti$^{4+}$ substitutes Mn$^{3+}$ at the B-site as shown by DFT.

Domain wall currents are intrinsic and robust.

Poole-Frenkel conductance dominates electronic transport.

Abstract

Acceptor and donor doping is a standard for tailoring semiconductors. More recently, doping was adapted to optimize the behavior at ferroelectric domain walls. In contrast to more than a century of research on semiconductors, the impact of chemical substitutions on the local electronic response at domain walls is largely unexplored. Here, the hexagonal manganite ErMnO$_3$ is donor doped with Ti$^{4+}$. Density functional theory calculations show that Ti$^{4+}$ goes to the B-site, replacing Mn$^{3+}$. Scanning probe microscopy measurements confirm the robustness of the ferroelectric domain template. The electronic transport at both macro- and nanoscopic length scales is characterized. The measurements demonstrate the intrinsic nature of emergent domain wall currents and point towards Poole-Frenkel conductance as the dominant transport mechanism. Aside from the new insight into the electronic properties of hexagonal manganites, B-site doping adds an additional degree of freedom for tuning the domain wall functionality.