1
|
Zhang Y, Wang T, Wang Z, Xing Z. Effects of Te- and Fe-doping on the superconducting properties in Fe ySe 1-xTe x thin films. Sci Rep 2022; 12:391. [PMID: 35013483 PMCID: PMC8748920 DOI: 10.1038/s41598-021-04403-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/10/2021] [Indexed: 11/08/2022] Open
Abstract
High quality FeySe1-xTex epitaxial thin films have been fabricated on TiO2-buffered SrTiO3 substrates by pulsed laser deposition technology. There is a significant composition deviation between the nominal target and the thin film. Te doping can affect the Se/Te ratio and Fe content in chemical composition. The superconducting transition temperature Tc is closely related to the chemical composition. Fe vacancies are beneficial for the FeySe1-xTex films to exhibit the higher Tc. A 3D phase diagram is given that the optimize range is x = 0.13-0.15 and y = 0.73-0.78 for FeySe1-xTex films. The anisotropic, effective pining energy, and critical current density for the Fe0.72Se0.94Te0.06, Fe0.76Se0.87Te0.13 and Fe0.91Se0.77Te0.23 films were studied in detail. The scanning transmission electron microscopy images display a regular atomic arrangement at the interfacial structure.
Collapse
Affiliation(s)
- Yalin Zhang
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, China
| | - Tong Wang
- Department of Mathematics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Zhihe Wang
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
- School of Physics, Nanjing University, Nanjing, 210093, China.
| | - Zhongwen Xing
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
- School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, China.
| |
Collapse
|
2
|
Obata Y, Sato M, Kondo Y, Yamaguchi Y, Karateev IA, Pavlov I, Vasiliev AL, Haindl S. Chemical Composition Control at the Substrate Interface as the Key for FeSe Thin-Film Growth. ACS APPLIED MATERIALS & INTERFACES 2021; 13:53162-53170. [PMID: 34698487 DOI: 10.1021/acsami.1c14451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The strong fascination exerted by the binary compound of FeSe demands reliable engineering protocols and more effective approaches toward inducing superconductivity in FeSe thin films. Our study addresses the peculiarities in pulsed laser deposition that determine FeSe thin-film growth and focuses on the film/substrate interface, which has only been considered hypothetically in the past literature. The FeSe/MgO interface has been assumed (1) to be clean and (2) to obey lattice-matching epitaxy. Our studies reveal that both assumptions are misleading and demonstrate the tendency for domain-matching epitaxial growth, which accompanies the problem of chemical heterogeneity. We propose that homogenization of the film/substrate interface by an Fe buffer can improve the control of stoichiometry and nanostrain in a way that favors superconductivity even in ultrathin FeSe films. We will also show that on a chemically homogenized FeSe/Fe interface, the control of film texture with preparation conditions is still possible.
Collapse
Affiliation(s)
- Yukiko Obata
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Michiko Sato
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Yuji Kondo
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Yuta Yamaguchi
- Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Igor A Karateev
- National Research Centre ″Kurchatov Institute,″ pl. Akademika Kurchatova 1, Moscow 123182, Russian Federation
| | - Ivan Pavlov
- Shubnikov Institute of Crystallography of FSRC "Crystallography and Photonics" Russian Academy of Sciences, Leninsky pr. 59, Moscow 119333, Russian Federation
| | - Alexander L Vasiliev
- National Research Centre ″Kurchatov Institute,″ pl. Akademika Kurchatova 1, Moscow 123182, Russian Federation
- Shubnikov Institute of Crystallography of FSRC "Crystallography and Photonics" Russian Academy of Sciences, Leninsky pr. 59, Moscow 119333, Russian Federation
- Moscow Institute of Physics and Technology, National Research University, Dolgoprudny, Moscow region 141701, Russian Federation
| | - Silvia Haindl
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| |
Collapse
|
3
|
Zhang HF, Chen XH, Xiao QL, Chen F, Feng Z, Cao S, Zhang J, Qi Y, Shi Z, Ge JY. Evolution of Superconducting Properties in Fe 1.1Se 0.8Te 0.2 Films Before and After Structure Avalanche. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42138-42145. [PMID: 34432434 DOI: 10.1021/acsami.1c10303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
By preparing a series of high-quality Fe1.1Se0.8Te0.2 films on the CaF2 substrate via pulsed laser deposition, we reveal the evolution of the structure as well as the superconductivity with the film thickness. We have found that there exists a threshold thickness above which the critical temperature Tc reaches its optimal value of 23.18 K with large activation energy, promising for high-field technological applications. Most importantly, the thick films have been found in a metastable state due to the fragile balance between the increased strain energy and the large compressive stress. Once the balance is broken by an external perturbation, a unique structure avalanche happens with a large part of the film exfoliated from the substrate and curves out. The exfoliated part of the film remains a single phase, with its lattice parameter and Tc recovering the bulk values. Our results clearly demonstrate the close relation between the compressive stress of the film/substrate interface and the high critical temperature observed in FeSeTe films. Moreover, this also provides an efficient way to fabricate free-standing single-phase FeSeTe crystals in the phase-separation regime.
Collapse
Affiliation(s)
- Han-Fang Zhang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Xing-Hong Chen
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Qi-Ling Xiao
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Fei Chen
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Zhenjie Feng
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Shixun Cao
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
- Department of Physics, Shanghai Key Laboratory for High Temperature Superconductors, Shanghai University, 200444 Shanghai, China
| | - Jincang Zhang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Yanpeng Qi
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhixiang Shi
- Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, 211189 Nanjing, China
| | - Jun-Yi Ge
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
- Department of Physics, Shanghai Key Laboratory for High Temperature Superconductors, Shanghai University, 200444 Shanghai, China
| |
Collapse
|
4
|
Huang Y, Wolowiec C, Zhu T, Hu Y, An L, Li Z, Grossman JC, Schuller IK, Ren S. Emerging Magnetic Interactions in van der Waals Heterostructures. NANO LETTERS 2020; 20:7852-7859. [PMID: 33054240 DOI: 10.1021/acs.nanolett.0c02175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Vertical van der Waals (vdWs) heterostructures based on layered materials are attracting interest as a new class of quantum materials, where interfacial charge-transfer coupling can give rise to fascinating strongly correlated phenomena. Transition metal chalcogenides are a particularly exciting material family, including ferromagnetic semiconductors, multiferroics, and superconductors. Here, we report the growth of an organic-inorganic heterostructure by intercalating molecular electron donating bis(ethylenedithio)tetrathiafulvalene into (Li,Fe)OHFeSe, a layered material in which the superconducting ground state results from the intercalation of hydroxide layer. Molecular intercalation in this heterostructure induces a transformation from a paramagnetic to spin-glass-like state that is sensitive to the stoichiometry of molecular donor and an applied magnetic field. Besides, electron-donating molecules reduce the electrical resistivity in the heterostructure and modify its response to laser illumination. This hybrid heterostructure provides a promising platform to study emerging magnetic and electronic behaviors in strongly correlated layered materials.
Collapse
Affiliation(s)
- Yulong Huang
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Christian Wolowiec
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Taishan Zhu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yong Hu
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Lu An
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Zheng Li
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Shenqiang Ren
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- Research and Education in Energy, Environment, and Water (RENEW) Institute, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| |
Collapse
|
5
|
Mei C, Lin Z, Zhang R, Xu C, Huang H, Dong Y, Meng M, Gao Y, Zhang X, Zhang Q, Gu L, Yang H, Tian H, Li J, Lu Y, Zhang G, Zhao Y. Growth of High-Quality Superconducting FeSe 0.5Te 0.5 Films on Pb(Mg 1/3Nb 2/3) 0.7Ti 0.3O 3 and Electric-Field Modulation of Superconductivity. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12238-12245. [PMID: 32052958 DOI: 10.1021/acsami.9b18749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Heterostructures composed of superconductor and ferroelectrics (SC/FE) are very important for manipulating the superconducting property and applications. However, growth of high-quality superconducting iron chalcogenide films is challenging because of their volatility and FE substrate with rough surface and large lattice mismatch. Here, we report a two-step growth approach to get high-quality FeSe0.5Te0.5 (FST) films on FE Pb(Mg1/3Nb2/3)0.7Ti0.3O3 with large lattice mismatch, which show superconductivity at only around 10 nm. Through a systematic study of structural and electric transport properties of samples with different thicknesses, a mechanism to grow high-quality FST is discovered. Moreover, electric-field-induced remarkable change of Tc (superconducting transition temperature) is demonstrated in a 20 nm FST film. This work paves the way to grow high-quality films which contain volatile element and have large lattice mismatch with the substrate. It is also helpful for manipulating the superconducting property in SC/FE heterostructures.
Collapse
Affiliation(s)
- Chenguang Mei
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Zhu Lin
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Ruixin Zhang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chengchao Xu
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Haoliang Huang
- CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory for Physical Sciences at the Microscale & National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Yongqi Dong
- CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory for Physical Sciences at the Microscale & National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Miao Meng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Ye Gao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Xi Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huaixin Yang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianqi Li
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yalin Lu
- CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory for Physical Sciences at the Microscale & National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Guangming Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| |
Collapse
|
6
|
Zhong W, Shen S, Feng S, Liu Y, Xu A, Ye X, Chen D. Distorted FeSe4 unit in ammonium ion intercalated FeSe superconductor. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2019.107605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
7
|
Comparative Review on Thin Film Growth of Iron-Based Superconductors. CONDENSED MATTER 2017. [DOI: 10.3390/condmat2030025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
8
|
Interface control by homoepitaxial growth in pulsed laser deposited iron chalcogenide thin films. Sci Rep 2015; 5:16334. [PMID: 26548645 PMCID: PMC4637838 DOI: 10.1038/srep16334] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/13/2015] [Indexed: 11/13/2022] Open
Abstract
Thin film growth of iron chalcogenides by pulsed laser deposition (PLD) is still a delicate issue in terms of simultaneous control of stoichiometry, texture, substrate/film interface properties, and superconducting properties. The high volatility of the constituents sharply limits optimal deposition temperatures to a narrow window and mainly challenges reproducibility for vacuum based methods. In this work we demonstrate the beneficial introduction of a semiconducting FeSe1−xTex seed layer for subsequent homoepitaxial growth of superconducting FeSe1−xTex thin film on MgO substrates. MgO is one of the most favorable substrates used in superconducting thin film applications, but the controlled growth of iron chalcogenide thin films on MgO has not yet been optimized and is the least understood. The large mismatch between the lattice constants of MgO and FeSe1−xTex of about 11% results in thin films with a mixed texture, that prevents further accurate investigations of a correlation between structural and electrical properties of FeSe1−xTex. Here we present an effective way to significantly improve epitaxial growth of superconducting FeSe1−xTex thin films with reproducible high critical temperatures (≥17 K) at reduced deposition temperatures (200 °C–320 °C) on MgO using PLD. This offers a broad scope of various applications.
Collapse
|
9
|
Lin Z, Mei C, Wei L, Sun Z, Wu S, Huang H, Zhang S, Liu C, Feng Y, Tian H, Yang H, Li J, Wang Y, Zhang G, Lu Y, Zhao Y. Quasi-two-dimensional superconductivity in FeSe0.3Te0.7 thin films and electric-field modulation of superconducting transition. Sci Rep 2015; 5:14133. [PMID: 26382136 PMCID: PMC4585655 DOI: 10.1038/srep14133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/13/2015] [Indexed: 11/26/2022] Open
Abstract
We report the structural and superconducting properties of FeSe0.3Te0.7 (FST) thin films with different thicknesses grown on ferroelectric Pb(Mg1/3Nb2/3)0.7Ti0.3O3 substrates. It was shown that the FST films undergo biaxial tensile strains which are fully relaxed for films with thicknesses above 200 nm. Electrical transport measurements reveal that the ultrathin films exhibit an insulating behavior and superconductivity appears for thicker films with Tc saturated above 200 nm. The current-voltage curves around the superconducting transition follow the Berezinskii-Kosterlitz-Thouless (BKT) transition behavior and the resistance-temperature curves can be described by the Halperin–Nelson relation, revealing quasi-two-dimensional phase fluctuation in FST thin films. The Ginzburg number decreases with increasing film thickness indicating the decrease of the strength of thermal fluctuations. Upon applying electric field to the heterostructure, Tc of FST thin film increases due to the reduction of the tensile strain in FST. This work sheds light on the superconductivity, strain effect as well as electric-field modulation of superconductivity in FST films.
Collapse
Affiliation(s)
- Zhu Lin
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Chenguang Mei
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Linlin Wei
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Zhangao Sun
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Shilong Wu
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Haoliang Huang
- CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory for Physical Sciences at the Microscale &National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Shu Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Chang Liu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Yang Feng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Huaixin Yang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Jianqi Li
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Yayu Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Guangming Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Yalin Lu
- CAS Key Laboratory of Materials for Energy Conversion, Hefei National Laboratory for Physical Sciences at the Microscale &National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| |
Collapse
|
10
|
Artefacts in geometric phase analysis of compound materials. Ultramicroscopy 2015; 157:91-7. [PMID: 26094205 DOI: 10.1016/j.ultramic.2015.05.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/13/2015] [Accepted: 05/23/2015] [Indexed: 12/29/2022]
Abstract
The geometric phase analysis (GPA) algorithm is known as a robust and straightforward technique that can be used to measure lattice strains in high resolution transmission electron microscope (TEM) images. It is also attractive for analysis of aberration-corrected scanning TEM (ac-STEM) images that resolve every atom column, since it uses Fourier transforms and does not require real-space peak detection and assignment to appropriate sublattices. Here it is demonstrated that, in ac-STEM images of compound materials with compositionally distinct atom columns, an additional geometric phase is present in the Fourier transform. If the structure changes from one area to another in the image (e.g. across an interface), the change in this additional phase will appear as a strain in conventional GPA, even if there is no lattice strain. Strategies to avoid this pitfall are outlined.
Collapse
|
11
|
Zhuang J, Yeoh WK, Cui X, Xu X, Du Y, Shi Z, Ringer SP, Wang X, Dou SX. Unabridged phase diagram for single-phased FeSe(x)Te(1-x) thin films. Sci Rep 2014; 4:7273. [PMID: 25449669 PMCID: PMC4250907 DOI: 10.1038/srep07273] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/05/2014] [Indexed: 11/16/2022] Open
Abstract
A complete phase diagram and its corresponding physical properties are essential prerequisites to understand the underlying mechanism of iron-based superconductivity. For the structurally simplest 11 (FeSeTe) system, earlier attempts using bulk samples have not been able to do so due to the fabrication difficulties. Here, thin FeSexTe1-x films with the Se content covering the full range (0 ≤ x ≤ 1) were fabricated by using pulsed laser deposition method. Crystal structure analysis shows that all films retain the tetragonal structure in room temperature. Significantly, the highest superconducting transition temperature (TC = 20 K) occurs in the newly discovered domain, i.e., 0.6 ≤ x ≤ 0.8. The single-phased superconducting dome for the full Se doping range is the first of its kind in iron chalcogenide superconductors. Our results present a new avenue to explore novel physics as well as to optimize superconductors.
Collapse
Affiliation(s)
- Jincheng Zhuang
- 1] Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, People's Republic of China [2] Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Wai Kong Yeoh
- 1] Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia [2] Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia [3] School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, New South Wales 2006, Australia
| | - Xiangyuan Cui
- 1] Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia [2] School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, New South Wales 2006, Australia
| | - Xun Xu
- Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Yi Du
- Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Zhixiang Shi
- Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, People's Republic of China
| | - Simon P Ringer
- 1] Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia [2] School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, New South Wales 2006, Australia
| | - Xiaolin Wang
- Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Shi Xue Dou
- Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| |
Collapse
|
12
|
Strain induced superconductivity in the parent compound BaFe2As2. Nat Commun 2014; 4:2877. [PMID: 24309386 DOI: 10.1038/ncomms3877] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 11/05/2013] [Indexed: 11/08/2022] Open
Abstract
The discovery of superconductivity with a transition temperature, Tc, up to 65 K in single-layer FeSe (bulk Tc=8 K) films grown on SrTiO3 substrates has attracted special attention to Fe-based thin films. The high Tc is a consequence of the combined effect of electron transfer from the oxygen-vacant substrate to the FeSe thin film and lattice tensile strain. Here we demonstrate the realization of superconductivity in the parent compound BaFe2As2 (no bulk Tc) just by tensile lattice strain without charge doping. We investigate the interplay between strain and superconductivity in epitaxial BaFe2As2 thin films on Fe-buffered MgAl2O4 single crystalline substrates. The strong interfacial bonding between Fe and the FeAs sublattice increases the Fe-Fe distance due to the lattice misfit, which leads to a suppression of the antiferromagnetic spin density wave and induces superconductivity with bulk Tc≈10 K. These results highlight the role of structural changes in controlling the phase diagram of Fe-based superconductors.
Collapse
|
13
|
Haindl S, Kidszun M, Oswald S, Hess C, Buchner B, Kolling S, Wilde L, Thersleff T, Yurchenko VV, Jourdan M, Hiramatsu H, Hosono H. Thin film growth of Fe-based superconductors: from fundamental properties to functional devices. A comparative review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:046502. [PMID: 24695004 DOI: 10.1088/0034-4885/77/4/046502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fe-based superconductors bridge a gap between MgB2 and the cuprate high temperature superconductors as they exhibit multiband character and transition temperatures up to around 55 K. Investigating Fe-based superconductors thus promises answers to fundamental questions concerning the Cooper pairing mechanism, competition between magnetic and superconducting phases, and a wide variety of electronic correlation effects. The question addressed in this review is, however, is this new class of superconductors also a promising candidate for technical applications? Superconducting film-based technologies range from high-current and high-field applications for energy production and storage to sensor development for communication and security issues and have to meet relevant needs of today’s society and that of the future. In this review we will highlight and discuss selected key issues for Fe-based superconducting thin film applications. We initially focus our discussion on the understanding of physical properties and actual problems in film fabrication based on a comparison of different observations made in the last few years. Subsequently we address the potential for technological applications according to the current situation.
Collapse
|
14
|
Ciechan A, Winiarski MJ, Samsel-Czekała M. Magnetic phase transitions and superconductivity in strained FeTe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:025702. [PMID: 24304545 DOI: 10.1088/0953-8984/26/2/025702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The influence of hydrostatic pressure and ab-plane strain on the magnetic structure of FeTe is investigated from first principles. The results of calculations reveal a phase transition from antiferromagnetic double-stripe ordering at ambient pressure to ferromagnetic ordering at 2 GPa, or under compressive strain reducing the lattice parameter a by about 3%. In turn, a tensile strain of less than 2% induces the phase transition to antiferromagnetic single-stripe ordering. It corresponds to the superconducting FeTe thin films, thereby confirming that the superconducting state is positively linked to single-stripe antiferromagnetic fluctuations. Both types of transition indicate that the position of Te atoms in the crystal is crucial for the magnetic and superconducting properties of iron chalcogenides.
Collapse
Affiliation(s)
- A Ciechan
- Institute of Physics, Polish Academy of Sciences, aleja Lotników 32/46, 02-668 Warsaw, Poland
| | | | | |
Collapse
|
15
|
Lin W, Li Q, Sales BC, Jesse S, Sefat AS, Kalinin SV, Pan M. Direct probe of interplay between local structure and superconductivity in FeTe₀.₅₅Se₀.₄₅. ACS NANO 2013; 7:2634-2641. [PMID: 23413999 DOI: 10.1021/nn400012q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The relationship between atomically defined structures and physical properties in functional materials remains a subject of constant interest. We explore the interplay between local crystallographic structure, composition, and local superconductive properties in iron chalcogenide superconductors. Direct structural analysis of scanning tunneling microscopy data allows local lattice distortions and structural defects across an FeTe0.55Se0.45 surface to be explored on a single unit-cell level. Concurrent superconducting gap (SG) mapping reveals suppression of the SG at well-defined structural defects, identified as a local structural distortion. The strong structural distortion causes the vanishing of the superconducting state. This study provides insight into the origins of superconductivity in iron chalcogenides by providing an example of atomic-level studies of the structure-property relationship.
Collapse
Affiliation(s)
- Wenzhi Lin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | | | | | | | | | | | |
Collapse
|
16
|
Wu MK, Wang MJ, Yeh KW. Recent advances in β-FeSe 1-x and related superconductors. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2013; 14:014402. [PMID: 27877558 PMCID: PMC5090576 DOI: 10.1088/1468-6996/14/1/014402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 11/20/2012] [Indexed: 06/06/2023]
Abstract
It has been more than four years since the discovery of β-FeSe1-x superconductors. Through the efforts of many outstanding research groups, unprecedented advances in the field have been achieved. High-quality single crystals of β-FeSe1-x and related compounds have been prepared by various techniques, allowing us to explore in detail the physical properties of this class of materials. Detailed characterizations of the structure and properties of these crystals have helped us to understand the origin of superconductivity in β-FeSe1-x . The occurrence of superconductivity is associated with the low-temperature structure distortion, which is accompanied by several anomalies. Recent measurements on quasiparticle and acoustic phonon dynamics with respect to the orbital modification in β-FeSe1-x suggest the opening of an energy gap below 130-140 K, accompanied by a coincident transfer of optical spectral weight in the visible range and alterations in transport properties. These observations provide convincing evidence that the modification of the electronic structure occurs prior to the lattice distortion. They further suggest that the high-temperature gap and the lattice symmetry breaking are driven by short-range orbital and/or charge orders.
Collapse
Affiliation(s)
- Maw-Kuen Wu
- Department of Physics, National Dong-Hwa University, Hualien, Taiwan
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Ming-Jye Wang
- Institute of Physics, Academia Sinica, Taipei, Taiwan
- Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
| | - Kuo-Wei Yeh
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
17
|
Mele P. Superconducting properties of iron chalcogenide thin films. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2012; 13:054301. [PMID: 27877514 PMCID: PMC5099615 DOI: 10.1088/1468-6996/13/5/054301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/20/2012] [Accepted: 10/03/2012] [Indexed: 06/03/2023]
Abstract
Iron chalcogenides, binary FeSe, FeTe and ternary FeTe x Se1-x , FeTe x S1-x and FeTe:O x , are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i) easy fabrication and epitaxial growth on common single-crystal substrates; (ii) strong enhancement of superconducting transition temperature with respect to the bulk parent compounds (in FeTe0.5Se0.5, zero-resistance transition temperature Tc0bulk = 13.5 K, but Tc0film = 19 K on LaAlO3 substrate); (iii) high critical current density (Jc ∼ 0.5 ×106 A cm2 at 4.2 K and 0 T for FeTe0.5Se0.5 film deposited on CaF2, and similar values on flexible metallic substrates (Hastelloy tapes buffered by ion-beam assisted deposition) with a weak dependence on magnetic field; (iv) high upper critical field (∼50 T for FeTe0.5Se0.5, Bc2(0), with a low anisotropy, γ ∼ 2). These highlights explain why thin films of iron chalcogenides have been widely studied in recent years and are considered as promising materials for applications requiring high magnetic fields (20-50 T) and low temperatures (2-10 K).
Collapse
|
18
|
Song CL, Wang YL, Jiang YP, Wang L, He K, Chen X, Hoffman JE, Ma XC, Xue QK. Suppression of superconductivity by twin boundaries in FeSe. PHYSICAL REVIEW LETTERS 2012; 109:137004. [PMID: 23030114 DOI: 10.1103/physrevlett.109.137004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Indexed: 06/01/2023]
Abstract
Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate twin boundaries in stoichiometric FeSe films grown by molecular beam epitaxy. Twin boundaries can be unambiguously identified by imaging the 90° change in the orientation of local electronic dimers from Fe site impurities on either side. Twin boundaries run at approximately 45° to the Fe-Fe bond directions, and noticeably suppress the superconducting gap, in contrast with the recent experimental and theoretical findings in other iron pnictides. Furthermore, vortices appear to accumulate on twin boundaries, consistent with the degraded superconductivity there. The variation in superconductivity is likely caused by the increased Se height in the vicinity of twin boundaries, providing the first local evidence for the importance of this height to the mechanism of superconductivity.
Collapse
Affiliation(s)
- Can-Li Song
- State Key Laboratory for Surface Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | | | | | | | | | | | | | | | | |
Collapse
|