  The Aharonov-Bohm (AB) effect is an important discovery of quantum theory. It
serves as a surprising quantum phenomenon in which an electrically charged
particle can be affected by an electromagnetic potential, despite being
confined to a region in which both the magnetic field and electric field are
zero. This fact gives the electromagnetic potentials greater significance in
quantum physics than in classical physics. The original AB effect belongs to an
``electromagnetic type". A certain vector potential is crucial for building a
certain type of AB effect. In this work, we focus on the ``spin", which is an
intrinsic property of microscopic particles that has been widely accepted
nowadays. First, we propose the hypothesis of spin vector potential by
considering a particle with a spin operator. Second, to verify the existence of
such a spin vector potential, we present a gedanken double-slit interference
experiment (i.e., the spin AB effect), which is possible to be observed in the
lab. Third, we apply the spin vector potential to naturally explain why there
were the Dzyaloshinsky-Moriya-type interaction and the dipole-dipole
interaction between spins, and also predict a new type of spin-orbital
interaction.
