Free-carrier dynamics in Au₂Pb probed by optical conductivity measurements

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• Dirac materials exhibit unique electronic properties with potential applications.
• Understanding the optical response is crucial for characterizing charge carrier behavior.

Purpose of the Study:

• To investigate the optical reflectivity and conductivity of the Dirac material Au2Pb.
• To determine the nature of charge carriers and their contribution to optical properties across a wide temperature range.

Main Methods:

• Measured optical reflectivity of Au2Pb from 30 to 48,000 cm⁻¹.
• Calculated optical conductivity from reflectivity data.
• Analyzed data for temperatures ranging from 9 K to 300 K.

Main Results:

• Optical conductivity is dominated by free carriers from topologically trivial bulk bands.
• The total plasma frequency of these carriers is temperature-independent.
• Au2Pb exhibits typical metallic optical response without signs of localization or bad-metal behavior.

Conclusions:

• The electronic properties of Au2Pb are primarily governed by bulk band contributions.
• The material behaves as a conventional metal, contrary to some expectations for Dirac materials.
• Further research can explore tuning these properties for electronic devices.