Publisher's Note: Robust determination of the superconducting gap sign structure via quasiparticle interference [Phys. Rev. B 92 , 184513 (2015)]
Physical review B
Phase-sensitive measurements of the superconducting gap in Fe-based superconductors have proven more difficult than originally anticipated. While quasiparticle interference (QPI) measurements based on scanning tunneling spectroscopy are often proposed as defnitive tests of gap structure, the analysis typically relies on details of the model employed. Here we point out that the temperature dependence of momentum-integrated QPI data can be used to identify gap sign changes in a qualitative way,
... d present an illustration for s_± and s_++ states in a system with typical Fe-pnictide Fermi surface.