Strain-induced improvements on piezoelectric and nonlinear optical properties of BiAlO3

Abstract

Using density functional theory, we calculate the effect of compressive and tensile strain on the electronic, piezoelectric, and nonlinear optical properties of BiAlO3. Our results show that applying strain effectively reduces the band gap of BiAlO3. Analysis of the piezoelectric constant shows that the tensile strain can significantly enhance the piezoelectricity of BiAlO3, while the change in the second harmonic generation (SHG) tensor under applied strain indicates that the nonlinear optical properties of BiAlO3 can also be effectively modulated by applying strain. Moreover, the SHG tensors d12 and d31 of strain-free BiAlO3 are even higher than that of LiNbO3. The noncentrosymmetric distortion of BiAlO3 resulting from its BiO12 cuboctahedron structure is the reason for its excellent SHG properties. However, compressive strain changes the main source of SHG from the BiO12 cuboctahedron to the AlO6 octahedron.