| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Alloys and Compounds for Thermoelectric and Solar Cell Applications XI
|
| Presentation Title |
Order-disorder Transitions in Zr-doped NbCoSn Heusler Alloys Enable Tunable n-p Transitions |
| Author(s) |
Nathan Johnson |
| On-Site Speaker (Planned) |
Nathan Johnson |
| Abstract Scope |
Thermoelectric NbCoSn heusler alloys have demonstrated a transition in carrier type as the unit cell is doped with increasing Co. The transition occurs near the half heusler composition. It has also been observed that the maximum Seebeck coefficient for either carrier type increases with shorter annealing times. We show that the n-p transition effect and the higher Seebeck coefficients are linked to an order-disorder transition in the NbCoSn unit cell near the half heusler composition. We use X-ray diffraction to solve the ordering of the unit cell at different compositions and annealing times. Diffraction experiments are coupled with thermoelectric property measurements. We then use a density functional theory approach to show how the change in unit cell ordering modifies the electronic structure of the crystal. As more Co is doped into the unit cell, the crystal experiences a symmetry change that likewise modifies the band structure and the carrier composition. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Electronic Materials, Energy Conversion and Storage |