在 SrTiO3 衬底上的高温超导 FeSe 薄膜。
High temperature superconducting FeSe films on SrTiO3 substrates.
机构信息
1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2].
1] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [3].
出版信息
Sci Rep. 2014 Aug 12;4:6040. doi: 10.1038/srep06040.
Interface enhanced superconductivity at two dimensional limit has become one of most intriguing research directions in condensed matter physics. Here, we report the superconducting properties of ultra-thin FeSe films with the thickness of one unit cell (1-UC) grown on conductive and insulating SrTiO3 (STO) substrates. For the 1-UC FeSe on conductive STO substrate (Nb-STO), the magnetization versus temperature (M-T) measurement shows a drop crossover around 85 K. For the FeSe films on insulating STO substrate, systematic transport measurements were carried out and the sheet resistance of FeSe films exhibits Arrhenius TAFF behavior with a crossover from a single-vortex pinning region to a collective creep region. More intriguing, sign reversal of Hall resistance with temperature is observed, demonstrating a crossover from hole conduction to electron conduction above TC in 1-UC FeSe films.
二维极限下的界面增强超导电性已成为凝聚态物理中最引人入胜的研究方向之一。在这里，我们报告了在导电和绝缘 SrTiO3（STO）衬底上生长的厚度为一个单胞（1-UC）的超薄 FeSe 薄膜的超导性能。对于在导电 STO 衬底（Nb-STO）上的 1-UC FeSe，磁化强度随温度（M-T）的测量显示在 85 K 左右出现下降交叉。对于绝缘 STO 衬底上的 FeSe 薄膜，进行了系统的输运测量，FeSe 薄膜的面电阻表现出 Arrhenius TAFF 行为，从单个涡旋钉扎区域到集体蠕变区域发生交叉。更有趣的是，观察到霍尔电阻随温度的符号反转，表明在 1-UC FeSe 薄膜中，在 TC 以上从空穴传导到电子传导的交叉。
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