  A first-principles density-functional-theory method has been used to
reinvestigate the mechanical and dynamical stability of the metallic phase of
AlH3 between 65-110 GPa. The electronic properties and phonon dynamics as a
function of pressure are also explored. We find electron-phonon
superconductivity in the cubic Pm-3n structure with critical temperature Tc =
37 K at 70 GPa which decreases rapidly with the increase of pressure. Further
unlike a previously calculated Tc value of 24 K at 110 GPa, we do not find any
superconductivity of significance at this pressure which is consistent with
experimental observation.
