title: Quasi-two-dimensional superconductivity in FeSe0.3Te0.7 thin films and electric-field modulation of superconducting transition.
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.
authors.affiliation: 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.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Lin
authors.affiliation: 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.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Mei
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Wei
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Zhangao
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Shilong
authors.initials: S
authors.lastname: Wu
authors.affiliation: 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.
authors.forename: Haoliang
authors.initials: H
authors.lastname: Huang
authors.affiliation: 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.
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
authors.affiliation: 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.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: 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.
authors.forename: Yang
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Huanfang
authors.initials: H
authors.lastname: Tian
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Huaixin
authors.initials: H
authors.lastname: Yang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Jianqi
authors.initials: J
authors.lastname: Li
authors.affiliation: 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.
authors.forename: Yayu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
authors.affiliation: 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.
authors.forename: Yalin
authors.initials: Y
authors.lastname: Lu
authors.affiliation: 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.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhao