Probing Efficient N-Type Lanthanide Dopants for Mg₃Sb₂ Thermoelectrics.

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectricity

Background:

• The discovery of n-type Mg3Sb2 has spurred research into effective n-type dopants.
• Identifying efficient dopants is crucial for advancing Mg3Sb2-based thermoelectric devices.

Purpose of the Study:

• To computationally screen lanthanide elements as potential n-type dopants for Mg3Sb2.
• To experimentally validate promising dopants and optimize thermoelectric performance through codoping.

Main Methods:

• First-principles defect calculations were used for systematic computational screening.
• Experimental synthesis and characterization of doped Mg3Sb2 samples.
• Evaluation of electron concentration, power factor, and thermoelectric figure of merit (zT).

Main Results:

• Nd, Gd, Ho, and Lu were identified as promising n-type dopants, achieving high electron concentrations.
• Experimental validation confirmed Nd and Tm as effective dopants, outperforming Te.
• Codoping with Nd (Tm) and Te enhanced power factor and reduced thermal conductivity, yielding high zT values (≈1.65-1.75 at 775 K).

Conclusions:

• Lanthanide elements, particularly Nd and Tm, are promising for developing efficient n-type Mg3Sb2 thermoelectrics.
• Codoping strategies can simultaneously improve power factor and reduce thermal conductivity.
• This research provides insights for designing high-performance Mg3Sb2 thermoelectric materials.