High temperature superconducting FeSe films on SrTiO3 substrates

Yi Sun; Wenhao Zhang; Ying Xing; Fangsen Li; Yanfei Zhao; Zhengcai Xia; Lili Wang; Xucun Ma; Qi-Kun Xue; Jian Wang

doi:10.1038/srep06040

High temperature superconducting FeSe films on SrTiO3 substrates

Sci Rep. 2014 Aug 12:4:6040. doi: 10.1038/srep06040.

Authors

Yi Sun¹, Wenhao Zhang², Ying Xing³, Fangsen Li⁴, Yanfei Zhao³, Zhengcai Xia⁵, Lili Wang⁶, Xucun Ma⁶, Qi-Kun Xue⁷, Jian Wang⁸

Affiliations

¹ 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2].
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].
³ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
⁴ 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.
⁵ Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 1037 Luoyu road, Wuhan 430071, China.
⁶ 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] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
⁷ 1] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
⁸ 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.

Abstract

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.

Publication types

Research Support, Non-U.S. Gov't