Machine Learned Interatomic Potential for Atomic Simulation of Dislocation in Ceramics

Dislocations in ceramics are rapidly catching interest owing to their exciting application potential for dislocation toughening of intrinsically brittle ceramics and functional property tailoring, and thus are now perceived as promising atomic-scale entities for next generation device applications [1-3]. However, understanding at the atomic scale of the dislocation behaviors in ceramics is still lacking. The traditional empirical interatomic potential of ceramics usually suffers the bad transferability and low accuracy. In this work, we reported the development of machine learned interatomic potential for the atomic simulation of dislocation in ceramics, i.e., zinc oxide (ZnO), gallium nitride (GaN), and strontium titanate (SrTiO3), yielding ab initial accuracy and large-scale atomic simulation (millions of atoms). The machine learned interatomic potentials describe well the core structure and slip barrier of dislocation in these ceramics comparing with the results of first-principles calculation and experiment. Finally, the indentation-induced dislocation nucleation and propagation in ceramics were studied using the developed interatomic potential, in good agreement with the nanoindentation experimental results. This study not only demonstrates the effectiveness of machine learned interatomic potentials in the analysis of plastic deformation of ceramic materials, but also provides new insights into the dislocation-dominated deformation behavior of ceramics. Authors acknowledge the JSPS Postdoctoral Fellowships for Research in Japan (Standard) and the Grant-in-Aid for JSPS Research Fellow Grant No. 22F22056.<br/> <br/><b>References</b><br/>[1] M. Höfling, et al. Control of polarization in bulk ferroelectrics by mechanical dislocation imprint. Science, 2021, 372(6545): 961-964.<br/>[2] M. Kissel, et al. Enhanced Photoconductivity at Dislocations in SrTiO3. Advanced Materials, 2022, 34(32): 2203032.<br/>[3] L. Porz, et al. Dislocation-toughened ceramics. Materials Horizons, 2021, 8(5): 1528-1537.