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Meng M, Liu S, Song D, Zhang X, Du H, Huang H, Liu H, Sun Z, Mei C, Yang H, Tian H, Lu Y, Zhang Y, Li J, Zhao Y. Magnetotransport property of oxygen-annealed Fe 1+yTe thin films. J Phys Condens Matter 2023; 35:305701. [PMID: 37102208 DOI: 10.1088/1361-648x/acce15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/18/2023] [Indexed: 06/19/2023]
Abstract
Fe-based superconductors are one of the current research focuses. FeTe is unique in the series of FeSe1-xTex, since it is nonsuperconducting near the FeTe side in the phase diagram in contrast to the presence of superconductivity in other region. However, FeTe thin films become superconducting after oxygen annealing and the mechanism remains elusive. Here, we report the temperature dependences of resistivity, Hall effect and magnetoresistance (MR) of a series of FeTe thin films with different amounts of excess Fe and oxygen. These properties show dramatic changes with excess Fe and oxygen incorporation. We found the Hall coefficients are positive for the oxygen-annealed samples, in contrast to the transition from positive to negative below 50 K for the vacuum-annealed samples. For all samples, both the resistivity and Hall coefficient show a dramatic drop, respectively, at around 50 K-75 K, implying coexistence of superconductivity and antiferromagnetic order for the oxygen-annealed samples. The vacuum-annealed samples show both positive and negative values of MR depending on temperature, while negative MR dominates for the oxygen-annealed samples. We also found that oxygen annealing reduces the excess Fe in FeTe, which has been neglected before. The results are discussed in terms of several contributions, and a comparison is made between the oxygen-annealed FeTe thin films and FeSe1-xTex. This work is helpful for shedding light on the understanding of oxygen-annealed FeTe thin films.
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Affiliation(s)
- Miao Meng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China
| | - Siqian Liu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China
| | - Dongsheng Song
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Xi Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China
| | - Haifeng Du
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, People's Republic of China
| | - Haoliang Huang
- Anhui Laboratory of Advanced Photon Science and Technology, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Huaying Liu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Zhangao Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Chenguang Mei
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China
| | - Huaixin Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yalin Lu
- Anhui Laboratory of Advanced Photon Science and Technology, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Yuzhong Zhang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Jianqi Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China
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Scholes DT, Hawks SA, Yee PY, Wu H, Lindemuth JR, Tolbert SH, Schwartz BJ. Overcoming Film Quality Issues for Conjugated Polymers Doped with F4TCNQ by Solution Sequential Processing: Hall Effect, Structural, and Optical Measurements. J Phys Chem Lett 2015; 6:4786-4793. [PMID: 26554820 DOI: 10.1021/acs.jpclett.5b02332] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate that solution-sequential processing (SqP) can yield heavily doped pristine-quality films when used to infiltrate the molecular dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) into pure poly(3-hexylthiophene) (P3HT) polymer layers. Profilometry measurements show that the SqP method produces doped films with essentially the same surface roughness as pristine films, and 2-D grazing-incidence wide-angle X-ray scattering (GIWAXS) confirms that SqP preserves both the size and orientation of the pristine polymer's crystallites. Unlike traditional blend-cast F4TCNQ/P3HT doped films, our sequentially processed layers have tunable and reproducible conductivities reaching as high as 5.5 S/cm even when measured over macroscopic (>1 cm) distances. The high conductivity and superb film quality allow for meaningful Hall effect measurements, which reveal p-type conduction and carrier concentrations tunable from 10(16) to 10(20) cm(-3) and hole mobilities ranging from ∼0.003 to 0.02 cm(2) V(-1) s(-1) at room temperature over the doping levels examined.
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Affiliation(s)
| | | | | | | | | | - Sarah H Tolbert
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Benjamin J Schwartz
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
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