Abstract
We apply the quasiparticle self-consistent approximation (QS) to some of the iron pnictide and chalcogenide superconductors. We compute Fermi surfaces and density of states, and find excellent agreement with experiment, substantially improving over standard band-structure methods. Analyzing the QS self-energy we discuss nonlocal and dynamic contributions to effective masses. We present evidence that the two contributions are mostly separable, since the quasiparticle weight is found to be essentially independent of momentum. The main effect of nonlocality is captured by the static but nonlocal QS effective potential. Moreover, these nonlocal self-energy corrections, absent in, e.g., dynamical mean field theory, can be relatively large. We show, on the other hand, that QS only partially accounts for dynamic renormalizations at low energies. These findings suggest that QS combined with dynamical mean field theory will capture most of the many-body physics in the iron pnictides and chalcogenides.
- Received 7 September 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.237010
© 2012 American Physical Society