Flexoelectricity in binary oxides

The flexoelectric effect (emergence of a polarization under a strain gradient) is significantly enhanced in ferroelectric materials near their phase transition point due to the softening of an optical polar phonon mode. In this study, we perform first-principles calculations on alkaline-earth-metal binary oxides (BaO, SrO, CaO) to investigate how the flexoelectric tensor changes with epitaxial strain. Our results show that the magnitude of the flexoelectric effect is enhanced near strain-induced phase transitions, highlighting the utility of strain in tuning this effect.