Possible s±-wave pairing evidenced by midgap surface bound states in Fe-pnictide superconductors

C. S. Liu*, J. Y. Chang, W. C. Wu, Chung Yu Mou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


A phenomenological theory of tunneling spectroscopy for Fe-pnictide superconductors is developed by taking into consideration asymmetric interface scattering between particle and holes. It is shown that, consistent with anti-phase s±-wave pairing, appreciable zero-energy surface bound states exist on the [100] surface of Fe-pnictide superconductors. However, in contrast to the [110] bound states in d-wave cuprate superconductors, these bound states arise as a result of non-conservation of momentum perpendicular to the interface for tunneling electrons and the s± pairing, and hence they can only exist in a small window (∼ ± 6°) in the orientation of edges near the [100] direction. Our results explain why a zero-bias conductance peak is often observed in tunneling spectroscopy and why, when it disappears, two coherent peaks show up. These results provide unambiguous signals to test for possible s±-wave pairing in Fe-pnictide superconductors.

Original languageEnglish
Article number365701
JournalJournal of Physics Condensed Matter
Issue number36
Publication statusPublished - 2013 Sept 11

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics


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