The spin polarization of current plays an important role in the performance of spintronic devices. Therefore, a highly spin -polarized current source has always been explored through various methods. We study the effects of magnetic order on the electronic structures of antiferromagnetic (AFM) MnBi 2 Te 4 films. A significant spin splitting is found in the surface states of a AFM MnBi 2 Te 4 film with three septuple layers (SLs). The AFM film can show typical metallic behavior for spin -down electrons, and exhibit a semiconductor or insulator behavior with a band gap at the Fermi level for spi...
