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Wu H, Zhao X, Guan C, Zhao LD, Wu J, Song D, Li C, Wang J, Loh KP, Venkatesan TV, Pennycook SJ. The Atomic Circus: Small Electron Beams Spotlight Advanced Materials Down to the Atomic Scale. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802402. [PMID: 30306651 DOI: 10.1002/adma.201802402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 08/06/2018] [Indexed: 06/08/2023]
Abstract
Defects in crystalline materials have a tremendous impact on their functional behavior. Controlling and tuning of these imperfections can lead to marked improvements in their physical, electrical, magnetic, and optical properties. Thanks to the development of aberration-corrected (scanning) transmission electron microscopy (STEM/TEM), direct visualization of defects at multiple length scales has now become possible, including those critically important defects at the atomic scale. Thorough understanding of the nature and dynamics of these defects is the key to unraveling the fundamental origins of structure-property relationships. Such insight can therefore allow the creation of new materials with desired properties through appropriate defect engineering. Herein, several examples of new insights obtained from representative functional materials are shown, including piezoelectrics/ferroelectrics, oxide interfaces, thermoelectrics, electrocatalysts, and 2D materials.
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Affiliation(s)
- Haijun Wu
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
| | - Xiaoxu Zhao
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore, 117456, Singapore
| | - Cao Guan
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
| | - Li-Dong Zhao
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Jiagang Wu
- Department of Materials Science, Sichuan University, Chengdu, 610064, China
| | - Dongsheng Song
- NUSNNI-NanoCore, National University of Singapore, Singapore, 117411, Singapore
| | - Changjian Li
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
| | - John Wang
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Thirumalai V Venkatesan
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
- NUSNNI-NanoCore, National University of Singapore, Singapore, 117411, Singapore
| | - Stephen J Pennycook
- Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore, 117574, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore, 117456, Singapore
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
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Zhang Q, Jin C, Xu H, Zhang L, Ren X, Ouyang Y, Wang X, Yue X, Lin F. Multiple-ellipse fitting method to precisely measure the positions of atomic columns in a transmission electron microscope image. Micron 2018; 113:99-104. [DOI: 10.1016/j.micron.2018.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
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Baiutti F, Gregori G, Suyolcu YE, Wang Y, Cristiani G, Sigle W, van Aken PA, Logvenov G, Maier J. High-temperature superconductivity at the lanthanum cuprate/lanthanum-strontium nickelate interface. NANOSCALE 2018; 10:8712-8720. [PMID: 29701210 DOI: 10.1039/c8nr00885j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The utilization of interface effects in epitaxial systems at the nanoscale has emerged as a very powerful approach for engineering functional properties of oxides. Here we present a novel structure fabricated by a state-of-the-art oxide molecular beam epitaxy method and consisting of lanthanum cuprate and strontium (Sr)-doped lanthanum nickelate, in which interfacial high-temperature superconductivity (Tc up to 40 K) occurs at the contact between the two phases. In such a system, we are able to tune the superconducting properties simply by changing the structural parameters. By employing electron spectroscopy and microscopy combined with dedicated conductivity measurements, we show that decoupling occurs between the electronic charge carrier and the cation (Sr) concentration profiles at the interface and that a hole accumulation layer forms, which dictates the resulting superconducting properties. Such effects are rationalized in the light of a generalized space-charge theory for oxide systems that takes account of both ionic and electronic redistribution effects.
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Affiliation(s)
- F Baiutti
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
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Wang Y, Huang MR, Salzberger U, Hahn K, Sigle W, van Aken PA. Towards atomically resolved EELS elemental and fine structure mapping via multi-frame and energy-offset correction spectroscopy. Ultramicroscopy 2018; 184:98-105. [DOI: 10.1016/j.ultramic.2017.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 11/28/2022]
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Suyolcu YE, Wang Y, Baiutti F, Al-Temimy A, Gregori G, Cristiani G, Sigle W, Maier J, van Aken PA, Logvenov G. Dopant size effects on novel functionalities: High-temperature interfacial superconductivity. Sci Rep 2017; 7:453. [PMID: 28352070 PMCID: PMC5428683 DOI: 10.1038/s41598-017-00539-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/28/2017] [Indexed: 12/03/2022] Open
Abstract
Among the range of complex interactions, especially at the interfaces of epitaxial oxide systems, contributing to the occurrence of intriguing effects, a predominant role is played by the local structural parameters. In this study, oxide molecular beam epitaxy grown lanthanum cuprate-based bilayers (consisting of a metallic (M) and an insulating phase (I)), in which high-temperature superconductivity arises as a consequence of interface effects, are considered. With the aim of assessing the role of the dopant size on local crystal structure and chemistry, and on the interface functionalities, different dopants (Ca2+, Sr2+ and, Ba2+) are employed in the M-phase, and the M–I bilayers are investigated by complementary techniques, including spherical-aberration-corrected scanning transmission electron microscopy. A series of exciting outcomes are found: (i) the average out-of-plane lattice parameter of the bilayers is linearly dependent on the dopant ion size, (ii) each dopant redistributes at the interface with a characteristic diffusion length, and (iii) the superconductivity properties are highly dependent on the dopant of choice. Hence, this study highlights the profound impact of the dopant size and related interface chemistry on the functionalities of superconducting oxide systems.
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Affiliation(s)
- Y Eren Suyolcu
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.
| | - Yi Wang
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Federico Baiutti
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Ameer Al-Temimy
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.,Al-Nahrain Nanorenewable Energy Research Center, Al-Nahrain University, Baghdad, Iraq
| | - Giuliano Gregori
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Georg Cristiani
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Wilfried Sigle
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Joachim Maier
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
| | - Gennady Logvenov
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany
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Baiutti F, Gregori G, Wang Y, Suyolcu YE, Cristiani G, van Aken PA, Maier J, Logvenov G. Cationic Redistribution at Epitaxial Interfaces in Superconducting Two-Dimensionally Doped Lanthanum Cuprate Films. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27368-27375. [PMID: 27648928 DOI: 10.1021/acsami.6b09739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The exploration of interface effects in complex oxide heterostructures has led to the discovery of novel intriguing phenomena in recent years and has opened the path toward the precise tuning of material properties at the nanoscale. One recent example is space-charge superconductivity. Among the complex range of effects which may arise from phase interaction, a crucial role is played by cationic intermixing, which defines the final chemical composition of the interface. In this work, we performed a systematic study on the local cationic redistribution of two-dimensionally doped lanthanum cuprate films grown by oxide molecular beam epitaxy, in which single LaO layers in the epitaxial crystal structure were substituted by layers of differently sized and charged dopants (Ca, Sr, Ba, and Dy). In such a model system, in which the dopant undergoes an asymmetric redistribution across the interface, the evolution of the cationic concentration profile can be effectively tracked by means of atomically resolved imaging and spectroscopic methods. This allowed for the investigation of the impact of the dopant chemistry (ionic size and charge) and of the growth conditions (temperature) on the final superconducting and structural properties. A qualitative model for interface cationic intermixing, based on thermodynamic considerations, is proposed. This work highlights the key role which cationic redistribution may have in the definition of the final interface properties and represents a further step forward the realization of heterostructures with improved quality.
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Affiliation(s)
- Federico Baiutti
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Giuliano Gregori
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Yi Wang
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Y Eren Suyolcu
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Georg Cristiani
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Joachim Maier
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Gennady Logvenov
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
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Wang Y, Salzberger U, Sigle W, Eren Suyolcu Y, van Aken PA. Oxygen octahedra picker: A software tool to extract quantitative information from STEM images. Ultramicroscopy 2016; 168:46-52. [DOI: 10.1016/j.ultramic.2016.06.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/21/2016] [Accepted: 06/06/2016] [Indexed: 10/21/2022]
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