Thermoelectric transport in Cu7PSe6 with high copper ionic mobility

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Binary superionic compounds like Cu2Se show good thermoelectric performance.
• A deeper understanding of phonon-liquid electron-crystal (PLEC) materials is needed.
• Argyrodite compounds offer a promising class of materials for studying PLEC properties.

Purpose of the Study:

• To investigate the thermoelectric transport properties of Cu7PSe6.
• To explore argyrodite-type compounds as a model system for PLEC materials.
• To understand the relationship between structure and properties in these materials.

Main Methods:

• Synthesis and characterization of Cu7PSe6.
• Measurement of thermoelectric transport properties.
• Analysis of thermal conductivity and its relation to lattice structure.

Main Results:

• Cu7PSe6 exhibits thermoelectric properties characteristic of PLEC materials.
• The compound shows exceptionally low thermal conductivity, below the glass limit.
• This low thermal conductivity is attributed to a molten copper sublattice and softened phonon modes.

Conclusions:

• Cu7PSe6 is a promising argyrodite-type thermoelectric material.
• The molten copper sublattice in Cu7PSe6 is key to its low thermal conductivity.
• Argyrodites are excellent model systems for advancing PLEC thermoelectric research.