Enhanced Electromechanical Coupling Near the Phase Boundary in Wurtzite (Mg,Zn)O and (Sc,Al)N

First-principles calculations revealed that (Mg,Zn)O and (Sc,Al)N have a tunable transition pressure from the wurtzite to rocksalt phase, which can be adjusted by the composition concentration. The piezoelectric response and electromechanical coupling show a clear enhancement near such a pressure-driven phase boundary. This suggests a new approach to designing novel piezoelectric materials with tunable piezoelectric response, driven by the external pressure.