Improper Inversion Symmetry Breaking and Piezoelectricity through Oxygen Octahedral Rotations in Layered Perovskite Family, Li R TiO 4 ( R = Rare Earths)
2015; Wiley; Volume: 2; Issue: 1 Linguagem: Inglês
10.1002/aelm.201500196
ISSN2199-160X
AutoresArnab Sen Gupta, Hirofumi Akamatsu, Megan E. Strayer, Shiming Lei, Toshihiro Kuge, Koji Fujita, Clarina dela Cruz, Atsushi Togo, Isao Tanaka, Katsuhisa Tanaka, Thomas E. Mallouk, Venkatraman Gopalan,
Tópico(s)Ferroelectric and Piezoelectric Materials
ResumoAn improper mechanism for breaking inversion symmetry is revealed and thus inducing piezoelectricity in the family of layered perovskites, Li R TiO 4 ( R = rare earths), which are previously reported as centrosymmetric. Noncentrosymmetry in this family of compounds arises from TiO 6 octahedral rotation represented by a − b o c o / b o a − c o in the perovskite blocks between R O rock salt and LiO antifluorite layers. X‐ray diffraction and optical second harmonic generation complemented by density functional theory predictions are crucial in determining the new structures. High transition temperature ( T ac ) of up to 1200 K from noncentrosymmetric to centrosymmetric phase is observed. Piezoelectric coefficients ( d 36 ) of up to −15 pC/N are predicted, and piezoelectric force microscopy experiments confirm a piezoelectric response. The demonstrated improper mechanism in this and other layered oxide families, with a wide range of available topologies and chemistries, could aid in the search for high temperature piezoelectrics.
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