Critical Role of Sc Substitution in Modulating Ferroelectricity in Multiferroic LuFeO3

Shiqing Deng; Jun Li; Didrik R Småbråten; Shoudong Shen; Wenbin Wang; Jun Zhao; Jing Tao; Ulrich Aschauer; Jun Chen; Yimei Zhu; Jing Zhu

doi:10.1021/acs.nanolett.1c02123

Critical Role of Sc Substitution in Modulating Ferroelectricity in Multiferroic LuFeO₃

Nano Lett. 2021 Aug 11;21(15):6648-6655. doi: 10.1021/acs.nanolett.1c02123. Epub 2021 Jul 20.

Authors

Shiqing Deng^{1

2

3}, Jun Li⁴, Didrik R Småbråten⁵, Shoudong Shen⁶, Wenbin Wang⁷, Jun Zhao⁶, Jing Tao³, Ulrich Aschauer⁵, Jun Chen¹, Yimei Zhu³, Jing Zhu²

Affiliations

¹ School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
² School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
³ Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States.
⁴ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁵ Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland.
⁶ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
⁷ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China.

PMID: 34283627
DOI: 10.1021/acs.nanolett.1c02123

Abstract

Understanding how individual dopants or substitutional atoms interact with host lattices enables us to manipulate, control, and improve the functionality of materials. However, because of the intimate coupling among various degrees of freedom in multiferroics, the atomic-scale influence of individual foreign atoms has remained elusive. Here, we unravel the critical roles of individual Sc substitutional atoms in modulating ferroelectricity at the atomic scale of typical multiferroics, Lu_1-xSc_xFeO₃, by combining advanced microscopy and theoretical studies. Atomic variations in polar displacement of intriguing topological vortex domains stabilized by Sc substitution are directly correlated with Sc atom-mediated local chemical and electronic fluctuations. The local FeO₅ trimerization magnitude and Lu/Sc-O hybridization strength are found to be significantly reinforced by Sc, clarifying the origin of the strong dependence of improper ferroelectricity on Sc content. This study could pave the way for correlating dopant-regulated atomic-scale local structures with global properties to engineer emergent functionalities of numerous chemically doped functional materials.

Keywords: electron microscopy; improper ferroelectricity; individual dopant; lutecium ferrite; multiferroics; structure−function relationship.