Direct Visualization of Irreducible Ferrielectricity in Crystals

Kai Du; Lei Guo; Jin Peng; Xing Chen; Zheng-Nan Zhou; Yang Zhang; Ting Zheng; Yan-Ping Liang; Jun-Peng Lu; Zhen-Hua Ni; Shan-Shan Wang; Gustaaf Van Tendeloo; Ze Zhang; Shuai Dong; He Tian

doi:10.1038/s41535-020-00252-y

arXiv · 2007.12828

Direct Visualization of Irreducible Ferrielectricity in Crystals

Kai Du·Lei Guo·Jin Peng·Xing Chen·Zheng-Nan Zhou·Yang Zhang·Ting Zheng·Yan-Ping Liang·Jun-Peng Lu·Zhen-Hua Ni·Shan-Shan Wang·Gustaaf Van Tendeloo·Ze Zhang·Shuai Dong·He Tian

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Abstract

In solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, e.g. ferroelectricity/ferromagnetism, antiferroelectricity/antiferromagnetism, and even dipole-vortex/magnetic-vortex, but ferrielectricity/ferrimagnetism kept telling a disparate story in microscopic level. Since the definition of a charge dipole involves more than one ion, there may be multiple choices for a dipole unit, which makes most ferrielectric orders equivalent to ferroelectric ones, i.e. this ferrielectricity is not necessary to be a real independent branch of polarity. In this work, by using the spherical aberration-corrected scanning transmission electron microscope, we visualize a nontrivial ferrielectric structural evolution in BaFe2Se3, in which the development of two polar sub-lattices is out-of-sync, for which we term it as irreducible ferrielectricity. Such irreducible ferrielectricity leads to a non-monotonic behavior for the temperature-dependent polarization, and even a compensation point in the ordered state. Our finding unambiguously distinguishes ferrielectrics from ferroelectrics in solids.

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Kai Du, Lei Guo, Jin Peng, Xing Chen, Zheng-Nan Zhou, Yang Zhang, Ting Zheng, Yan-Ping Liang, Jun-Peng Lu, Zhen-Hua Ni, Shan-Shan Wang, Gustaaf Van Tendeloo, Ze Zhang, Shuai Dong, He Tian. 2020-07-25. Direct Visualization of Irreducible Ferrielectricity in Crystals. https://doi.org/10.1038/s41535-020-00252-y

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