  We study the formation of Pop III stars by performing radiation hydrodynamics
simulations for three different initial clouds extracted from cosmological
hydrodynamics simulations. Starting from the cloud collapse stage, we follow
the growth of protostars by accretion for $\sim 10^5$ yr until the radiative
feedback from the protostars suppresses the accretion and the stellar
properties are nearly fixed. We find that the Pop III stars form in massive and
wide binaries/small-multiple stellar systems, with masses $>30\,M_\odot$ and
separations $>2000$ au. We also find that the properties of the final stellar
system correlate with those of the initial clouds: the total mass increases
with the cloud-scale accretion rate, and the angular momentum of the binary
orbit matches that of the initial cloud. While the total mass of the system in
our simulations is consistent with our previous single-star formation
simulations, individual masses are lower due to mass sharing, suggesting
potential modification in the extent of feedback from Pop III stars in the
subsequent evolution of the Universe. We also identify such systems as
mini-binaries embedded in a wider outer multiple-star system, which could
evolve into progenitors for observed gravitational wave events.
