Electronic quality factor for thermoelectrics.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Thermoelectric material development traditionally relies on extensive trial-and-error synthesis and characterization.
• Existing methods for evaluating thermoelectric performance are often time-consuming and require optimized samples.

Purpose of the Study:

• To introduce a new, simplified metric, the electronic quality factor (B), for predicting maximum thermoelectric power factor.
• To establish a universal relationship applicable across diverse thermoelectric materials.
• To provide a tool for efficient evaluation and guidance in thermoelectric material development.

Main Methods:

• Estimation of the electronic quality factor (B) from a single measurement of Seebeck coefficient and electrical conductivity at an arbitrary temperature.
• Analysis of thousands of experimental data points across dozens of materials to identify a universal curve.
• Investigation of deviations in B with temperature and doping to reveal underlying physical phenomena.

Main Results:

• A universal curve and a single material parameter (B) effectively describe experimental thermoelectric data for material classes.
• Deviations in B indicate significant effects like band convergence or altered scattering mechanisms.
• p-type GeTe and n-type Mg3SbBi alloys are identified as competitive alternatives to Bi2Te3 near room temperature.

Conclusions:

• The electronic quality factor (B) offers a powerful and convenient method for evaluating and guiding thermoelectric material discovery.
• This approach significantly accelerates the identification of promising thermoelectric materials.
• The findings highlight the potential of GeTe and Mg3SbBi alloys for near-room-temperature thermoelectric applications.