Improper Inversion Symmetry Breaking and Piezoelectricity through Oxygen Octahedral Rotations in Layered Perovskite Family, LiRTiO4 (R = Rare Earths). (7th December 2015)

• Record Type: Journal Article
• Authors: Gupta, Arnab Sen; Akamatsu, Hirofumi; Strayer, Megan E.; Lei, Shiming; Kuge, Toshihiro; Fujita, Koji; dela Cruz, Clarina; Togo, Atsushi; Tanaka, Isao; Tanaka, Katsuhisa; Mallouk, Thomas E.; Gopalan, Venkatraman
• Is Part Of: Advanced Electronic Materials. Volume 2:Number 1(2016)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2015-12-07
• Subjects: layered perovskite -- octahedral rotation -- piezoelectricity; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.201500196
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract : An improper mechanism for breaking inversion symmetry is revealed and thus inducing piezoelectricity in the family of layered perovskites, Li R TiO4 ( R = rare earths), which are previously reported as centrosymmetric. Noncentrosymmetry in this family of compounds arises from TiO6 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. Abstract : A new family of piezoelectrics in Rud­dlesden–Popper derivative Li R TiO4 ( R = rare earths) layered perovskites is reported. The mechanism for inversion symmetry breaking in this family of ­compounds is attributed to the oxygen ­octahedral rotations. The noncentrosymmetric to centrosymmetric phase transition temperatures are ≈800 K and above depending on the size of the rare earth ion.