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Zhang Q, Xie L, Liu G, Prokhorenko S, Nahas Y, Pan X, Bellaiche L, Gruverman A, Valanoor N. Nanoscale Bubble Domains and Topological Transitions in Ultrathin Ferroelectric Films. Adv Mater 2017; 29:1702375. [PMID: 29064154 DOI: 10.1002/adma.201702375] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/10/2017] [Indexed: 06/07/2023]
Abstract
Observation of a new type of nanoscale ferroelectric domains, termed as "bubble domains"-laterally confined spheroids of sub-10 nm size with local dipoles self-aligned in a direction opposite to the macroscopic polarization of a surrounding ferroelectric matrix-is reported. The bubble domains appear in ultrathin epitaxial PbZr0.2 Ti0.8 O3 /SrTiO3 /PbZr0.2 Ti0.8 O3 ferroelectric sandwich structures due to the interplay between charge and lattice degrees of freedom. The existence of the bubble domains is revealed by high-resolution piezoresponse force microscopy (PFM), and is corroborated by aberration-corrected atomic-resolution scanning transmission electron microscopy mapping of the polarization displacements. An incommensurate phase and symmetry breaking is found within these domains resulting in local polarization rotation and hence impart a mixed Néel-Bloch-like character to the bubble domain walls. PFM hysteresis loops for the bubble domains reveal that they undergo an irreversible phase transition to cylindrical domains under the electric field, accompanied by a transient rise in the electromechanical response. The observations are in agreement with ab-initio-based calculations, which reveal a very narrow window of electrical and elastic parameters that allow the existence of bubble domains. The findings highlight the richness of polar topologies possible in ultrathin ferroelectric structures and bring forward the prospect of emergent functionalities due to topological transitions.
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Affiliation(s)
- Qi Zhang
- School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Lin Xie
- National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA, 92697, USA
| | - Guangqing Liu
- School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Sergei Prokhorenko
- Theoretical Materials Physics Q-MAT CESAM, University of Liège, Sart Tilman, B-4000, Belgium
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA, 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Alexei Gruverman
- Department of Physics and Astronomy, University of Nebraska, Lincoln, NE, 68588, USA
| | - Nagarajan Valanoor
- School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
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Xie L, Li L, Heikes CA, Zhang Y, Hong Z, Gao P, Nelson CT, Xue F, Kioupakis E, Chen L, Schlom DG, Wang P, Pan X. Giant Ferroelectric Polarization in Ultrathin Ferroelectrics via Boundary-Condition Engineering. Adv Mater 2017; 29:1701475. [PMID: 28585347 DOI: 10.1002/adma.201701475] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/20/2017] [Indexed: 06/07/2023]
Abstract
Tailoring and enhancing the functional properties of materials at reduced dimension is critical for continuous advancement of modern electronic devices. Here, the discovery of local surface induced giant spontaneous polarization in ultrathin BiFeO3 ferroelectric films is reported. Using aberration-corrected scanning transmission electron microscopy, it is found that the spontaneous polarization in a 2 nm-thick ultrathin BiFeO3 film is abnormally increased up to ≈90-100 µC cm-2 in the out-of-plane direction and a peculiar rumpled nanodomain structure with very large variation in c/a ratios, which is analogous to morphotropic phase boundaries (MPBs), is formed. By a combination of density functional theory and phase-field calculations, it is shown that it is the unique single atomic Bi2 O3-x layer at the surface that leads to the enhanced polarization and appearance of the MPB-like nanodomain structure. This finding clearly demonstrates a novel route to the enhanced functional properties in the material system with reduced dimension via engineering the surface boundary conditions.
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Affiliation(s)
- Lin Xie
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA
- National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, P. R. China
| | - Linze Li
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA
| | - Colin A Heikes
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Yi Zhang
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA
| | - Zijian Hong
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, 16802, USA
| | - Peng Gao
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Christopher T Nelson
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Fei Xue
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, 16802, USA
| | - Emmanouil Kioupakis
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Longqing Chen
- Department of Materials Science and Engineering, Pennsylvania State University, State College, PA, 16802, USA
| | - Darrel G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Peng Wang
- National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, P. R. China
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA
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Wang Y, Chen W, Wang B, Zheng Y. Ultrathin Ferroelectric Films: Growth, Characterization, Physics and Applications. Materials (Basel) 2014; 7:6377-6485. [PMID: 28788196 PMCID: PMC5456150 DOI: 10.3390/ma7096377] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/31/2014] [Accepted: 08/08/2014] [Indexed: 11/23/2022]
Abstract
Ultrathin ferroelectric films are of increasing interests these years, owing to the need of device miniaturization and their wide spectrum of appealing properties. Recent advanced deposition methods and characterization techniques have largely broadened the scope of experimental researches of ultrathin ferroelectric films, pushing intensive property study and promising device applications. This review aims to cover state-of-the-art experimental works of ultrathin ferroelectric films, with a comprehensive survey of growth methods, characterization techniques, important phenomena and properties, as well as device applications. The strongest emphasis is on those aspects intimately related to the unique phenomena and physics of ultrathin ferroelectric films. Prospects and challenges of this field also have been highlighted.
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Affiliation(s)
- Ying Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Weijin Chen
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Biao Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Yue Zheng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
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