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 alpha phase to an insulating layered structure of space group Pnma at 34 GPa, and a transition to a semimetallic Pm (3) over barn phase at 73 GPa. These phases are predicted to be stable against dehydridation (the evolution of H-2 molecules), and they could be formed at pressures easily attainable within diamond-anvil-cell experiments.