Microscopic scale investigation of piezoelectric properties of lead-free alkaline niobates

Abstract

A first-principles-based technique is used to investigate the electromechanical properties oflead-free alkaline niobates. In particular, we study the structural and piezoelectric properties of LixK1-x NbO3 which is taken as a prototypical solid solution. We show that the system develops an orthorhombic to tetragonal polymorphic phase transition at room temperature for a Li concentration of 4.5%. We showed that not only the phase coexistence region is relevant for the enhancement of the piezoelectric properties but also the off-center Li impurities play an important role in the improvement of the electromechanical response.