Abstract
We investigate the normal state of the “11” iron-based superconductor by angle-resolved photoemission. Our data reveal a highly renormalized quasiparticle dispersion characteristic of a strongly correlated metal. We find sheet dependent effective carrier masses between corresponding to a mass enhancement over band structure values of . This is nearly an order of magnitude higher than the renormalization reported previously for iron-arsenide superconductors of the “1111” and “122” families but fully consistent with the bulk specific heat.
- Received 29 November 2009
DOI:https://doi.org/10.1103/PhysRevLett.104.097002
©2010 American Physical Society