Abstract
We investigate the quasiparticle interference (QPI) in Fe-based superconductors in both the -wave and -wave superconducting states on the basis of the five-orbital model. In the octet model for cuprate superconductors with -wave state, the QPI signal due to the impurity scattering at () disappears when the gap functions at and have the same sign. However, we show that this extinction rule does not hold in Fe-based superconductors with fully gapped -wave state. The reason is that the resonance condition is not satisfied under the experimental condition for Fe-based superconductors. We perform the detailed numerical study of the QPI signal using the -matrix approximation, and show that the experimentally observed QPI peak around can be explained on the basis of both the -wave and -wave states. Furthermore, we discuss the magnetic field dependence of the QPI by considering the Zeeman effect, and find that the field-induced suppression of the peak intensity around can also be explained in terms of both the -wave and -wave states.
1 More- Received 17 November 2014
- Revised 18 May 2015
DOI:https://doi.org/10.1103/PhysRevB.92.045124
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