  The discovery of new high-temperature superconductors is one of the most
critical problems in materials, chemistry, and physics. This work
systematically investigates fluorite-like structures of XBeH8 (X is Ac, Th, Pa,
U, and Np) to gain physical insight into the pressure effects on the
properties. Our results reveal that AcBeH8 and ThBeH8 are two potential
high-temperature superconductors, where AcBeH8 reaching a superconducting
transition temperature of 284.11 K at 150 GPa and even a value of 203.29 K at
50 GPa, ThBeH8 has Tc is 217.65 K at 200 GPa, and the predicted results provide
strong candidates for achieving high temperature or even room temperature
superconductivity. The analysis of pressure effects demonstrates unusual charge
transfer and atomic structure in the system, with s-f migration in Ac/Th atoms
and s-p migration in Be atoms, similar to the high-pressure behavior of
alkaline earth metals. In the past long time, superconductivity and magnetism
were considered unable to coexist. However, UBeH8 and NpBeH8 are two potential
magnetic superconductors with maximum Tc of 60.70 and 107.18 K at 100 and 350
GPa, respectively, and Hubbard U calculations predict their magnetic moments
with 1.52 to 1.90 and 2.49 to 2.92 muB at 0 K. The coexistence of magnetic and
superconducting states may be attributed to the different sublattice actions.
