Imaging Se diffusion across the FeSe/SrTiO_3 interface

Monolayer FeSe on SrTiO_3 superconducts with reported T_\mathrm{c} as high as 100 K, but the dramatic interfacial T_\mathrm{c} enhancement remains poorly understood. Oxygen vacancies in SrTiO_3 are known to enhance the interfacial electron doping, electron-phonon coupling, and superconducting gap, but the detailed mechanism is unclear. Here we apply scanning transmission... Show more