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Constructing Localized Van Der Waals Gaps in Cubic-Phase GeMnTe2 Thermoelectric Material.
Mingrui Zhang1, Lingling Wei2, Tingting Yang3
1Key Laboratory for Macromolecular Science of Shaanxi Province and Shaanxi Key Laboratory for Advanced Energy Devices, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, China.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|November 3, 2025
Summary
Cubic GeMnTe2 offers a cost-effective alternative for thermoelectric devices. Alloying with Sb2Te3 and Pb substitution significantly boosted its performance by optimizing thermal conductivity and electrical properties.
Area of Science:
- Materials Science
- Solid State Physics
- Energy Conversion
Background:
- Rhombohedral GeTe is a leading thermoelectric material for medium temperatures.
- Cubic GeMnTe2 presents a lower-cost alternative with higher structural symmetry.
- Phase stability and engineering potential are key advantages of cubic GeMnTe2.
Purpose of the Study:
- To enhance the thermoelectric performance of cubic GeMnTe2.
- To investigate the effects of Sb2Te3 alloying and Pb substitution.
- To explore strategies for improving thermoelectric materials for medium-temperature applications.
Main Methods:
- Synthesis of Sb2Te3-alloyed and Pb-substituted cubic GeMnTe2.
- Characterization of structural, electrical, and thermal properties.
- Analysis of phonon scattering mechanisms and band structure modifications.
Main Results:
- Achieved a peak figure of merit (ZT) of ≈1.5 at 773 K.
- Obtained an average ZT of ≈0.96 over the 323-823 K range.
- Sb2Te3 alloying created localized van der Waals gaps, reducing lattice thermal conductivity.
- Pb substitution optimized hole concentration for improved power factor.
Conclusions:
- Cubic GeMnTe2 demonstrates superior thermoelectric performance compared to rhombohedral GeTe.
- Localized van der Waals gaps are effective in enhancing thermoelectric properties.
- This approach provides a pathway for developing advanced cubic or pseudo-cubic thermoelectric materials.
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