Quasiparticle interference in Fe-based superconductors based on a five-orbital tight-binding model

Youichi Yamakawa and Hiroshi Kontani
Phys. Rev. B 92, 045124 – Published 27 July 2015

Abstract

We investigate the quasiparticle interference (QPI) in Fe-based superconductors in both the s++-wave and s±-wave superconducting states on the basis of the five-orbital model. In the octet model for cuprate superconductors with dx2y2-wave state, the QPI signal due to the impurity scattering at q=kikj (E=|Δ(ki)|, i=18) disappears when the gap functions at ki and kj have the same sign. However, we show that this extinction rule does not hold in Fe-based superconductors with fully gapped s-wave state. The reason is that the resonance condition E=|Δ(ki)| is not satisfied under the experimental condition for Fe-based superconductors. We perform the detailed numerical study of the QPI signal using the T-matrix approximation, and show that the experimentally observed QPI peak around q2=(π,0) can be explained on the basis of both the s++-wave and s±-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 q2 can also be explained in terms of both the s++-wave and s±-wave states.

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  • Received 17 November 2014
  • Revised 18 May 2015

DOI:https://doi.org/10.1103/PhysRevB.92.045124

©2015 American Physical Society

Authors & Affiliations

Youichi Yamakawa* and Hiroshi Kontani

  • Department of Physics, Nagoya University, Furo-cho, Nagoya 464-8602, Japan

  • *yamakawa@s.phys.nagoya-u.ac.jp

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Issue

Vol. 92, Iss. 4 — 15 July 2015

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