Mixed-state effect on quasiparticle interference in iron-based superconductors
1 Department of Physics and Institute of Theoretical Physics, Nanjing Normal University Nanjing, Jiangsu, 210046, China
2 Department of Physics, Shanghai University - Shanghai 200444, China
Received: 17 July 2012
Accepted: 12 October 2012
Based on a phenomenological model with s± or s-wave pairing symmetry, the mixed-state effect on quasiparticle interference in iron-based superconductors is investigated by solving large-scale Bogoliubov-de Gennes equations based on the Chebyshev polynomial expansion. Taking into account the presence of magnetic field, our result for the s± pairing is in qualitative agreement with recent scanning tunneling microscopy experiment while for the s-wave pairing, the result is in apparent contradiction with experimental observations, thus excluding the s-wave pairing. Furthermore, we treat the effect of vortices rigorously instead of approximating the vortices as magnetic impurities, thus our results are robust and should be more capable of explaining the experimental data.
PACS: 74.70.Xa – Pnictides and chalcogenides / 74.55.+v – Tunneling phenomena: single particle tunneling and STM / 74.25.Op – Mixed states, critical fields, and surface sheaths
© EPLA, 2012