1201.5694 (Qing-Yan Wang et al.)

Interface induced high temperature superconductivity in single unit-cell
FeSe films on SrTiO3    [PDF]

Qing-Yan Wang, Zhi Li, Wen-Hao Zhang, Zuo-Cheng Zhang, Jin-Song Zhang, Wei Li, Hao Ding, Yun-Bo Ou, Peng Deng, Kai Chang, Jing Wen, Can-Li Song, Ke He, Jin-Feng Jia, Shuai-Hua Ji, Yayu Wang, Lili Wang, Xi Chen, Xucun Ma, Qi-Kun Xue

Searching for superconducting materials with high transition temperature (TC)
is one of the most exciting and challenging fields in physics and materials
science. Although superconductivity has been discovered for more than 100
years, the copper oxides are so far the only materials with TC above 77 K, the
liquid nitrogen boiling point. Here we report an interface engineering method
for dramatically raising the TC of superconducting films. We find that one
unit-cell (UC) thick films of FeSe grown on SrTiO3 (STO) substrates by
molecular beam epitaxy (MBE) show signatures of superconducting transition
above 50 K by transport measurement. A superconducting gap as large as 20 meV
of the 1 UC films observed by scanning tunneling microcopy (STM) suggests that
the superconductivity could occur above 77 K. The occurrence of
superconductivity is further supported by the presence of superconducting
vortices under magnetic field. Our work not only demonstrates a powerful way
for finding new superconductors and for raising TC, but also provides a
well-defined platform for systematic study of the mechanism of unconventional
superconductivity by using different superconducting materials and substrates.

View original: http://arxiv.org/abs/1201.5694