Probing order parameter sign changes in d-wave and g-wave superconductors through quasiparticle interference

Abstract

The pairing mechanism of electrons in unconventional superconductors generally gives rise to a sign-changing superconducting order parameter, the details of which bear interesting information on the mechanism of superconductivity in these materials. However, probing the pairing symmetry of the gap remains a challenge as present experimental techniques are limited in their ability to probe the sign structure of the order parameter. In this paper, we study the order parameter structure through the method proposed by Hirschfeld, Altenfeld, Eremin and Mazin (HAEM) for scanning tunneling microscopy. Starting from the characteristic scattering vectors established by the octet model that connect the contours of constant energy of the superconducting Bogoliubov quasiparticles, we present qualitative and numerical arguments that establish the utility of the HAEM method in probing the order-parameter sign structure of exotic superconductors beyond the familiar d-wave ones.