Quasiparticle interference (QPI) by means of scanning tunneling microscopy/spectroscopy (STM/STS), angle resolved photoemission spectroscopy (ARPES), and multi-orbital tight bind- ing calculations are used to investigate the band structure and superconducting order parameter of LiFeAs. Using this combination we identify intra- and interband scattering vectors between the hole (h) and electron (e) bands in the QPI maps. Discrepancies in the band dispersions inferred from previous ARPES and STM/STS are reconciled by recognizing a difference in the kz sensitivity for the two probes. The observation of both h-h and e-h scattering is exploited using phase-sensitive scattering selection rules for Bogoliubov quasiparticles. From this we infer an s± gap structure, where a sign change occurs in the superconducting order parameter between the e and h bands.
@article{arxiv.1308.4413,
title = {Sign inversion in the superconducting order parameter of LiFeAs inferred from Bogoliubov quasiparticle interference},
author = {Shun Chi and S. Johnston and G. Levy and S. Grothe and R. Szedlak and B. Ludbrook and Ruixing Liang and P. Dosanjh and S. A. Burke and A. Damascelli and D. A. Bonn and W. N. Hardy and Y. Pennec},
journal= {arXiv preprint arXiv:1308.4413},
year = {2014}
}
Comments
Replaced previous version after the paper was accepted for publication in PRB