  The ability to generate and tune quantized persistent supercurrents is
crucial for building superconducting or atomtronic devices with novel
functionalities. In ultracold atoms, previous methods for generating quantized
supercurrents are generally based on dynamical processes to prepare atoms in
metastable excited states. Here we show that arbitrary quantized circulation
states can be adiabatically prepared and tuned as the ground state of a
ring-shaped Bose-Einstein condensate by utilizing spin-orbital-angular-momentum
(SOAM) coupling and an external potential. There exists superfluid hysteresis
for tuning supercurrents between different quantization values with nonlinear
atomic interactions, which is explained by developing a nonlinear Landau-Zener
theory. Our work will provide a powerful platform for studying SOAM coupled
ultracold atomic gases and building novel atomtronic circuits.
