Superconductivity of lanthanum hydride synthesized using AlH3 as a hydrogen source

Hydrogen-rich compounds show high-Tc superconductivity related to dense hydrogen under extremely high pressure (above 100 GPa). A recent investigation to search for high-Tc superconductive hydrides has advanced a synthesis technique using infrared laser heating of a hydrogen source material under conditions of extremely high pressure and temperature. In order to find a suitable synthesis route for high-Tc superconductive hydrides, the selection of a hydrogen source material has to be considered. In this study, the synthesis of hydrogen-rich lanthanum hydrides (LaHx) was performed using aluminium trihydride (AlH3) as the hydrogen source. Simple lanthanum on AlH3 was pressurized at 150 GPa and heated by infrared laser irradiation. After the laser heating, superconductivity at Tc ∼ 70 K was observed at 170 GPa. This indicates that LaHx (x < 10) was synthesized using AlH3 as the hydrogen source under conditions of extremely high pressure.