Imaging the Electron-Boson Coupling in Superconducting FeSe Films Using a Scanning Tunneling Microscope

Authors

Canli Song, Tsinghua University, Chinese Academy of Sciences, Harvard University
Yi-Lin Wang, Chinese Academy Of Sciences
Yeping Jiang, Tsinghua University, Chinese Academy of Sciences
Zhi Li, Chinese Academy of SciencesFollow
Lili Wang, Chinese Academy of Sciences
Ke He, Chinese Academy of Sciences
Xi Chen, Tsinghua University
Jennifer E. Hoffman, Harvard University
Xu-Cun Ma, Chinese Academy of Sciences
Qi-Kun Xue, Tsinghua University, Chinese Academy of SciencesFollow

RIS ID

115194

Publication Details

Song, C., Wang, Y., Jiang, Y., Li, Z., Wang, L., He, K., Chen, X., Hoffman, J. E., Ma, X. & Xue, Q. (2014). Imaging the Electron-Boson Coupling in Superconducting FeSe Films Using a Scanning Tunneling Microscope. Physical Review Letters, 112 057002-1-057002-5.

Abstract

Scanning tunneling spectroscopy has been used to reveal signatures of a bosonic mode in the local quasiparticle density of states of superconducting FeSe films. The mode appears below Tc as a "dip-hump" feature at energy Ω ∼ 4.7kBTc beyond the superconducting gap Δ. Spectra on strained regions of the FeSe films reveal simultaneous decreases in Δ and Ω. This contrasts with all previous reports on other high-Tc superconductors, where Δ locally anticorrelates with Ω. A local strong coupling model is found to reconcile the discrepancy well, and to provide a unified picture of the electron-boson coupling in unconventional superconductors.