Pressure-induced hydrogen-dominant metallic state in aluminum hydride

Phys Rev Lett. 2008 Feb 1;100(4):045504. doi: 10.1103/PhysRevLett.100.045504. Epub 2008 Jan 29.


Two structural transitions in covalent aluminum hydride AlH3 were characterized at high pressure. A metallic phase stable above 100 GPa is found to have a remarkably simple cubic structure with shortest first-neighbor H-H distances ever measured except in H2 molecule. Although the high-pressure phase is predicted to be superconductive, this was not observed experimentally down to 4 K over the pressure range 120-164 GPa. The results indicate that the superconducting behavior may be more complex than anticipated.