Magnetic quadratic nodal line with spin–orbital coupling in CrSb

Quadratic nodal lines (QNLs) with quadratic band splitting in the Brillouin zone have different properties from conventional linear nodal lines. In this study, based on symmetry analysis and first-principles calculation, we prove that magnetic quadratic nodal line (MQNL) exists in antiferromagnetic configurations of one single realistic solid-state material CrSb with the P63′/m′m′c structure that breaks the time-reversal symmetry. In magnetic systems with the non-negligible spin–orbit coupling effect, we show that nodal lines with a quadratic leading order dispersion can be realized around Fermi level. Moreover, CrSb shows four long Fermi arcs near Fermi energy level resulting from six pairs of Weyl points with opposite chirality. Our results reveal a promising platform for exploring the topological states with intriguing effects. We hope that the proposed realistic material can be viewed as ideal candidate to realize the MQNL in solid-state materials.