Superconductivity of lanthanum hydride synthesized using AlH ₃ as a hydrogen source

Abstract

Abstract Hydrogen-rich compounds show high- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:math> superconductivity related to dense hydrogen under extremely high pressure (above 100 GPa). A recent investigation to search for high- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:math> 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- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:math> superconductive hydrides, the selection of a hydrogen source material has to be considered. In this study, the synthesis of hydrogen-rich lanthanum hydrides (LaH x ) was performed using aluminium trihydride (AlH 3 ) as the hydrogen source. Simple lanthanum on AlH 3 was pressurized at 150 GPa and heated by infrared laser irradiation. After the laser heating, superconductivity at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msub> </mml:math> ∼ 70 K was observed at 170 GPa. This indicates that LaH x (x <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>&lt;</mml:mo> </mml:math> 10) was synthesized using AlH 3 as the hydrogen source under conditions of extremely high pressure.