Unusual metallic state in superconducting A15-type La₄H₂₃

Area of Science:

• Condensed matter physics
• Materials science
• Superconductivity research

Background:

• Hydride superconductors are key to achieving near room-temperature superconductivity.
• Research focuses on enhancing the superconducting transition temperature (Tc) in hydrides.
• Extreme conditions like high pressure, temperature, and magnetic fields offer new insights.

Purpose of the Study:

• To investigate the transport properties of a novel hydride superconductor under extreme conditions.
• To explore the electronic and magnetic behavior of A15-type La₄H₂₃.
• To understand superconductivity in conventional hydrides through high magnetic field studies.

Main Methods:

• Synthesis of cubic A15-type La₄H₂₃.
• Measurement of superconducting transition temperature (Tc) at high pressures (118 GPa).
• Investigation of transport properties, including magnetoresistance, in strong pulsed magnetic fields (up to 68 T).
• Construction of the magnetic phase diagram.

Main Results:

• La₄H₂₃ exhibits superconductivity with a Tc of 105 K at 118 GPa.
• A significant negative magnetoresistance was observed in the non-superconducting state below 40 K.
• Anomalous electronic structural properties were revealed under high magnetic fields.
• The full magnetic phase diagram up to 68 T was established.

Conclusions:

• A15-La₄H₂₃ presents an unusual metallic state and unique quantum transport behaviors.
• High magnetic field studies are crucial for understanding hydride superconductors.
• This research advances the fundamental knowledge of superconductivity in hydrides.