Evolution of defect signatures at ferroelectric domain walls in Mg-doped LiNbO3

TL;DR

This study investigates how magnesium doping affects defect structures at ferroelectric domain walls in lithium niobate, revealing defect stabilization and signature variations detectable via Raman spectroscopy.

Contribution

It provides new insights into defect evolution at domain walls in Mg-doped LiNbO3 using Raman spectroscopy, highlighting differences between bulk and wall defect signatures.

Findings

Defects are stabilized at domain walls.

Raman mode shifts reveal defect structure changes with Mg concentration.

Distinct defect signatures at bulk and domain walls.

Abstract

The domain structure of uniaxial ferroelectric lithium niobate single crystals is investigated using Raman spectroscopy mapping. The influence of doping with magnesium and poling at room temperature is studied by analysing frequency shifts at domain walls and their variations with dopant concentration and annealing conditions. It is shown that defects are stabilized at domain walls and that changes in the defect structures with Mg concentration can be probed by the shift of Raman modes. We show that the signatures of polar defects in the bulk and at the domain walls differ.