Piezoelectricity in n = 2 Ruddlesden–Popper Ferroelectric Oxides

High Resolution Image Download MS PowerPoint Slide We present first-principles calculations of piezoelectric tensors for the n = 2 Ruddlesden–Popper ferroelectrics Ca 3 Ti 2 O 7, Sr 3 Zr 2 O 7, Sr 3 Sn 2 O 7, and Li 2 SrNb 2 O 7 . Our computed longitudinal piezoelectric coefficients are comparable to the intrinsic coefficients of prototypical perovskite ferroelectrics. We identify an unusual form of transverse piezoelectricity in Ca 3 Ti 2 O 7 and Li 2 SrNb 2 O 7, where one transverse piezoelectric coefficient is negative and the other is positive. Furthermore, we show that octahedral rotation distortions, which are coupled to the polarization in this family of layered ferroelectrics, can tune the amplitudes of the piezoelectric coefficients.