  Hydrides offer an opportunity to study high-temperature (Tc)
superconductivity at experimentally achievable pressures. However, they
remained extremely high. Using density functional theory calculations, herein
we demonstrated that a newly rare earth hydride, namely bulk ErH2, could be
superconducting with a Tc around 80 K at 14.5 GPa. To date, the drived pressure
is the lowest reported value for compressed hydrides. Besides
superconductivity, Fermi Surface nesting and Kondo effect were manifested at
this pressure. Intriguingly, due to Kondo destruction, superconductivity was
prone to exist at 15 GPa. Under the rest of applied pressures, we also revealed
a gap of band structure at 20 GPa on the background of normal metallic states.
At 20 GPa, this compressed system could act as a host of superconductor being
judged from a sharp jump of spontaneous magnetic susceptibility with an
evanescent spin density of state at Fermi level along with the competition
between spin density wave and superconductivity. Finally, electron pairing glue
for ErH2 at these three typical pressures was attributed to the
antiferromagnetic spin fluctuation.
