Room-temperature bulk plasticity and tunable dislocation densities in KTaO3

TL;DR

This study demonstrates that single-crystal KTaO3 exhibits room-temperature bulk plasticity mediated by dislocations, with tunable dislocation densities and plastic zones, challenging the conventional view of its brittleness.

Contribution

It provides the first comprehensive experimental evidence of room-temperature plasticity in KTaO3 and introduces a method to control dislocation densities in this material.

Findings

Dislocations enable plasticity in KTaO3 at room temperature.

Dislocation densities and plastic zone sizes can be tuned.

Activated slip system identified as <110>{1-10}.

Abstract

We report room-temperature bulk plasticity mediated by dislocations in single-crystal cubic KTaO3, contrasting the conventional knowledge that single-crystal KTaO3 is susceptible to brittle cleavage. A mechanics-based combinatorial experimental approach using cyclic Brinell indentation, scratching, and uniaxial bulk compression consistently demonstrates room-temperature dislocation plasticity in KTaO3 from the mesoscale to the macroscale. This approach also delivers tunable dislocation densities and plastic zone sizes. Scanning transmission electron microscopy analysis underpins the activated slip system to be <110>{1-10}. Given the growing significance of KTaO3 as an emerging electronic oxide and the increasing interest in dislocations for tuning physical properties of oxides, our findings are expected to trigger synergistic research interest in KTaO3 with dislocations.