Metallization of aluminum hydride at high pressures: A first-principles study

We have used first-principles density-functional-theory electronic structure methods and a random searching technique to identify stable high pressure phases of aluminum hydride (AlH₃). We find a transition from the insulating low-pressure α phase to an insulating layered structure of space group $Pnma$ at 340.3em0exGPa, and a transition to a semimetallic Pm3̄n phase at 730.3em0exGPa. These phases are predicted to be stable against dehydridation (the evolution of H₂ molecules), and they could be formed at pressures easily attainable within diamond-anvil-cell experiments.