Room‐temperature bulk plasticity and tunable dislocation densities in KTaO$_3$

We report room-temperature bulk plasticity mediated by dislocations in single-crystal cubic KTaO$_3$, contrasting the conventional knowledge that single-crystal KTaO$_3$ 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 KTaO$_3$ 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 KTaO$_3$ 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 KTaO$_3$ with dislocations.