Evidence of nematic order and nodal superconducting gap along [110] direction in RbFe2As2

Abstract

Exotic electronic order may emerge and intertwine with superconductivity in iron-based superconductors. Here, the authors observe asymmetric electronic and superconducting gap structure in heavily hole-doped RbFe2As2 along the (π, π) and (π, -π) directions in reciprocal space, suggesting a novel (π, π) nematic phase emerging.