| Autor: |
Yox, Philip, Cerasoli, Frank T., Sarkar, Arka, Amobi, Genevieve, Viswanathan, Gayatri, Voyles, Jackson, Lebedev, Oleg l., Donadio, Davide, Kovnir, Kirill |
| Zdroj: |
Chemistry of Materials; April 2024, Vol. 36 Issue: 8 p3925-3932, 8p |
| Abstrakt: |
The type I clathrate, Ba8Cu16As30, is reinvestigated and found to have a low-temperature polymorph mP108-Ba8Cu16As30with ordered Cu and As sites. In situtemperature-dependent powder X-ray diffraction experiments guided synthetic efforts toward the synthesis of the ordered monoclinic (mP108) and disordered cubic (cP54) polymorphs with high phase purity. While a transition from mP108-Ba8Cu16As30to cP54-Ba8Cu16As30is not directly observed, cP54-Ba8Cu16As30is stabilized through quenching from high temperatures and is confirmed through high-resolution synchrotron powder X-ray diffraction. Combined theoretical predictions and experimental observations of the thermoelectric properties of both polymorphs reveal that the ordering of Cu and As atoms in the clathrate framework simultaneously enhances the Seebeck coefficient and electronic conductivity by increasing the hole effective mass and reducing the electronic scattering events. Consequently, the zTof mP108-Ba8Cu16As30reaches a maximum of 0.2 at 575 K, an order of magnitude higher than that of cP54-Ba8Cu16As30. |
| Databáze: |
Supplemental Index |
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