Unusual change in the electronic structure of a semimetal NdSb across the magnetic transition**

The rare-earth monopnictide (REM) materials host complex magnetic ground states and have recently attracted considerable research interest as it serves as a promising platform to investigate the interplay between strong electron correlation and topological phases. Here, we have reported a systematic investigation of the Fermi surface and the band dispersion of a correlated semimetal NdSb in the paramagnetic (PM) phase as well as the antiferromagnetic (AFM) phase (T_N ~ 15 K) using angle-resolved photoemission spectroscopy (ARPES). Our data reveals a clear distinct band evolution phenomenon due to the antiferromagnetic phase transition. Most importantly, a complex band structure is observed at the zone center which is potentially due to the strong hybridization induced by the magnetic phase transition. Our experimental study opens up a new path to understand the intricate interplay between magnetism, and electron correlation in this REM family.