Correlation of Fe-based Superconductivity and Electron-Phonon Coupling   in an FeAs/Oxide Heterostructure
  Interfacial phonons between iron-based superconductors (FeSCs) and perovskite substrates have received considerable attention due to the possibility of enhancing preexisting superconductivity. Using scanning tunneling spectroscopy, we studied the correlation between superconductivity and e-ph interaction with interfacial-phonons in an iron-based superconductor Sr$_2$VO$_3$FeAs ($T_c \approx$ 33 K) made of alternating FeSC and oxide layers. The quasiparticle interference measurement over regions with systematically different average superconducting gaps due to the e-ph coupling locally modulated by O vacancies in VO$_2$ layer, and supporting self-consistent momentum-dependent Eliashberg calculations provide a unique real-space evidence of the forward-scattering interfacial phonon contribution to the total superconducting pairing. 
Seokhwan Choi, Steven Johnston, Won-Jun Jang, Klaus Koepernik, Ken   Nakatsukasa, Jong Mok Ok, Hyun-Jung Lee, Hyun Woo Choi,...
cond-mat.supr-con