Electronic structure and spin polarization of Co/black phosphorus interface

•The inverted spin polarization can be attributed to the interface hybridization between Co and BP.•The outermost BP lattice is destroyed at the initial deposition of Co.•There is no chemical reaction between Co and BP or unbonded P.•An interface dipole is observed at the Co/BP interface. We studied the electronic properties and spin polarization of the interface between Co and black phosphorus (BP) with ultraviolet, X-ray and spin-resolved photoemission spectroscopy. The results show that the outermost BP is destroyed and the unbonded P is produced in the process of Co deposition. There is no chemical reaction and an interface dipole is found at the Co/BP interface. The SR-UPS results show that there is an inverted spin polarization near EF and the spin polarization is about positive 10%, which is attributed to the interface hybridization between Co and BP.