Detecting Superconductivity in the High Pressure Hydrides and Metallic Hydrogen from Optical Properties

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• High-pressure hydrides exhibit high-temperature superconductivity, crucial for future technologies.
• Measuring the critical temperature (Tc) in these materials often requires complex, lead-based techniques.
• Understanding the superconducting order parameter's temperature dependence is key.

Purpose of the Study:

• To develop a novel, leadless technique for measuring the critical temperature (Tc) in electron-phonon-driven superconducting hydrides.
• To establish a method that relies on optical reflectance measurements.
• To provide a more accessible way to characterize high-Tc superconducting materials.

Main Methods:

• A new optical reflectance technique is proposed, eliminating the need for sample electrical connections.
• The method analyzes reflectance in a specific spectral region above the optical gap and maximum phonon energy.
• The temperature dependence of reflectance is measured at a fixed photon energy to identify a cusp at Tc.

Main Results:

• The reflectance was found to mirror the temperature variation of the superconducting order parameter.
• A distinct cusp in the reflectance-temperature dependence was observed at the critical temperature (Tc).
• The technique allows for precise measurement of Tc without direct electrical contact.

Conclusions:

• The proposed leadless optical reflectance technique offers a reliable method for determining Tc in superconducting hydrides.
• This technique is particularly relevant for materials like metallic hydrogen and other high-energy phonon-coupled hydrides.
• The method simplifies the characterization of novel superconducting materials under extreme conditions.