An exemplary spin-polarized electron source includes a cathode, and a one-dimensional nanostructure made of a compound (e.g., group III-V) semiconductor with local polarized gap states. The one-dimensional nanostructure includes a first end portion electrically connected with the cathode and a second end portion located/directed away from the cathode. The second end portion of the one-dimensional nanostructure functions as a polarized electron emission tip and is configured (i.e., structured and arranged) for emitting a spin-polarized electron current/beam under an effect of selectably one of a magnetic field induction and a circularly polarized light beam excitation when a predetermined negative bias voltage is applied to the cathode. Furthermore, a spin-polarized scanning tunneling microscope incorporating such a spin-polarized electron source is also provided.