Magnetotransport property of oxygen-annealed Fe1+ yTe thin films

Miao Meng; Siqian Liu; Dongsheng Song; Xi Zhang; Haifeng Du; Haoliang Huang; Huaying Liu; Zhangao Sun; Chenguang Mei; Huaixin Yang; Huanfang Tian; Yalin Lu; Yuzhong Zhang; Jianqi Li; Yonggang Zhao

doi:10.1088/1361-648X/acce15

Magnetotransport property of oxygen-annealed Fe_{1+ y}Te thin films

J Phys Condens Matter. 2023 Apr 27;35(30). doi: 10.1088/1361-648X/acce15.

Authors

Miao Meng^{1

2}, Siqian Liu^{1

2}, Dongsheng Song³, Xi Zhang^{1

2}, Haifeng Du⁴, Haoliang Huang⁵, Huaying Liu⁶, Zhangao Sun⁷, Chenguang Mei^{1

2}, Huaixin Yang⁷, Huanfang Tian⁷, Yalin Lu^{5

8}, Yuzhong Zhang⁶, Jianqi Li⁷, Yonggang Zhao^{1

2}

Affiliations

¹ Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, People's Republic of China.
² Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, People's Republic of China.
³ Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China.
⁴ 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.
⁵ 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.
⁶ 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.
⁷ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
⁸ 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.

PMID: 37102208
DOI: 10.1088/1361-648X/acce15

Abstract

Fe-based superconductors are one of the current research focuses. FeTe is unique in the series of FeSe_1-xTe_x, 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 FeSe_1-xTe_x. This work is helpful for shedding light on the understanding of oxygen-annealed FeTe thin films.

Keywords: Hall effect measurements; electrical resistivity/conductivity; film; laser deposition; superconductor.