Plain s-wave superconductivity in single-layer FeSe on SrTiO3 probed by scanning tunnelling microscopy

By Q. Fan, Wei Zhang, Xiaohan Liu, Yajun Yan, M. Ren, R. Peng, Hao Xu, B. Xie, Jiuning Hu, Tong Zhang and 1 more. Nature Physics, 2015

153 citations recorded by the source corpus.

Single-layer FeSe film on SrTiO3(001) has recently come to the fore as an interfacial superconducting system, with a transition temperature that is significantly enhanced with respect to bulk FeSe. The mechanism for this enhancement, and indeed for the superconductivity itself, is therefore of great interest. Although the film has a simple Fermi surface topology, its pairing symmetry is unclear. By using low-temperature scanning tunnelling microscopy, we have systematically investigated the superconductivity of single-layer FeSe/SrTiO3 films, and report a fully gapped tunnelling spectrum and magnetic vortex lattice in the film. Quasi-particle interference patterns reveal scatterings between and within the electron pockets, and put constraints on possible pairing symmetries. By introducing impurity atoms onto the sample, we show that magnetic impurities such as Cr and Mn can locally suppress the superconductivity, but non-magnetic impurities (Zn, Ag and K) do not. Our results indicate that single-layer FeSe/SrTiO3 has a plain s-wave pairing symmetry, with an order parameter that has the same phase on all Fermi surface sections. A scanning tunnelling microscopy study of monolayer FeSe on strontium titanate reveals that this intriguing system has a plain s-wave pairing symmetry.

Subfields: Accounting, Condensed Matter Physics, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/54314f0ebbb966f2bbdc4e95d843caa0e836d46d

Citations in the corpus