Complex electronic structure evolution in a rare-earth based monopnictide*

In pursuit of intriguing topological phases, the rare-earth monopnictide (REM) family, which has magnetic ground states that exhibit high magnetoresistance, has emerged to be a growing field of research. Here, we study the evolution of the electronic structure of the candidate REM Dirac semimetal NdSb across the magnetic transition by using high-resolution angle-resolved photoemission spectroscopy along with first-principles density functional-theory based modeling. Three arc-like features in the zone corner and a complex band structure resembling an angel's wing have been discovered. It is revealed that the magnetic transition is what causes this drastic reconstruction of the itinerant bands surrounding the zone center: Specifically, in the antiferromagnetic phase, the Nd 5d electron band backfolds at the Γ point and hybridizes with the Sb 5p hole bands. Our study indicates that antiferromagnetism plays an intricate role in the electronic structure of the REM family.