  Samarium hydrides, belonging to the broad class of lanthanide polyhydrides,
have yet to be experimentally tested at high pressure. In this study, we use
random structure searches to explore multiple possible stoichiometries and
propose SmH$_2$ with a layered hexagonal structure in the $P6/mmm$ space group
and SmH$_6$ with hydrogen clathrate structures in the Im-3m space group as
theoretically stable phases of samarium hydrides at a wide range of pressures
centered around $200$ GPa. We further combine the first-principles methods of
density functional theory and dynamical mean-field theory to explore many-body
correlations in samarium hydrides, reporting electron and phonon dispersions
and densities of states, and also evaluate the electron-phonon driven
superconductivity to investigate low critical temperatures at $200$ GPa.
