Architecture of nanoscale ferroelectric domains in GaMo4S8

TL;DR

This study investigates the nanoscale ferroelectric domain structures in GaMo4S8 using local-probe imaging and bulk measurements, revealing complex hierarchical domain architectures and topological defects related to its phase transition.

Contribution

It provides detailed insight into the hierarchical ferroelectric domain structures and topological defects in GaMo4S8, advancing understanding of orbitally driven phase transitions in lacunar spinels.

Findings

Hierarchical domain structures on 10-100 nm scale

Presence of various ferroelectric domain boundaries and junctions

Identification of topological line defects transforming neutral walls

Abstract

Local-probe imaging of the ferroelectric domain structure and auxiliary bulk pyroelectric measurements were conducted at low temperatures with the aim to clarify the essential aspects of the orbitally driven phase transition in GaMo4S8, a lacunar spinel crystal that can be viewed as a spin-hole analogue of its GaV4S8 counterpart. We employed multiple scanning probe techniques combined with symmetry and mechanical compatibility analysis to uncover the hierarchical domain structures, developing on the 10-100 nm scale. The identified domain architecture involves a plethora of ferroelectric domain boundaries and junctions, including primary and secondary domain walls in both electrically neutral and charged configurations, and topological line defects transforming neutral secondary walls into two oppositely charged ones.