Electric-Field-Induced Domain Walls in Wurtzite Ferroelectrics

TL;DR

This study uncovers the atomic and electronic structures of electric-field-induced domain walls in wurtzite ferroelectric ScGaN, revealing metallic mid-gap states and a universal charge-compensation mechanism with implications for nanoelectronic devices.

Contribution

It provides the first detailed atomic and electronic characterization of domain walls in wurtzite ferroelectrics, highlighting a novel charged domain wall with unique electronic properties.

Findings

Revealed a charged domain wall with a buckled hexagonal phase

Discovered metallic-like mid-gap states at the domain walls

Demonstrated reconfigurable conductivity of the domain walls

Abstract

Wurtzite ferroelectrics possess transformative potential for next-generation microelectronics. A comprehensive understanding of their ferroelectric properties and domain energetics is crucial for tailoring their ferroelectric characteristics and exploiting their functional properties in practical devices. Despite burgeoning interest, the exact configurations, and electronic structures of the domain walls in wurtzite ferroelectrics remain elusive. In this work, we elucidate the atomic configurations and electronic properties of electric-field-induced domain walls in ferroelectric ScGaN. By combining transmission electron microscopy and theoretical calculations, a novel charged domain wall with a buckled two-dimensional hexagonal phase is revealed. The dangling bonds associated with these domain walls give rise to unprecedented metallic-like mid-gap states within the forbidden band. Quantitative analysis further unveils a universal charge-compensation mechanism stabilizing antipolar domain walls in ferroelectric materials, wherein the polarization discontinuity at the 180{\deg} domain wall is compensated by the dangling bond electrons. Furthermore, the reconfigurable conductivity of these domain walls is experimentally demonstrated, showcasing their potential for ultra-scaled device applications. Our findings represent a pivotal advancement in understanding the structural and electronic properties of wurtzite ferroelectric domain walls and lay the groundwork for fundamental physics studies and device applications.