Room-Temperature Plasticity of a Nanosized GaN Crystal

GaN wurtzite crystal is commonly regarded as eminently brittle. However, our research demonstrates that nanodeconfined GaN compressed along the M direction begins to exhibit room-temperature plasticity, yielding a dislocation-free structure despite the occurrence of considerable, irreversible deformation. Our interest in M-oriented, strained GaN nano-objects was sparked by the results of first-principles bandgap calculations, whereas subsequent nanomechanical tests and ultrahigh-voltage (1250 kV) transmission electron microscopy observations confirmed the authenticity of the phenomenon. Moreover, identical experiments along the C direction produced only a quasi-brittle response. Precisely how this happens is demonstrated by molecular dynamics simulations of the deformation of the C- and M-oriented GaN frustum, which mirror our nanopillar crystals.

Automated summary

The research reveals that nanodeconfined GaN compressed along the M direction exhibits room-temperature plasticity, while the response along the C direction is quasi-brittle. First-principles bandgap calculations, nanomechanical tests, and ultrahigh-voltage transmission electron microscopy observations confirm the authenticity of the phenomenon. Molecular dynamics simulations demonstrate how this process occurs in C- and M-oriented GaN frustum, reflecting nanopillar crystals.