Abstract
We have attempted to improve the thermoelectric performance of an Al–Si–Ru semiconducting approximant through optimizing the carrier concentration. The effects of Cu doping on the thermoelectric properties of an Al–Si–Ru semiconducting quasicrystalline approximant with the nominal composition of are investigated. At approximately room temperature, an increase of leads to a decrease of the Seebeck coefficient and an increase of the electrical conductivity. Density functional theory and the Boltzmann transport theory are used to calculate as the hole concentration and the band gap are varied. The temperature dependence of is quantitatively described by an increase of the hole concentration and narrowing of the band gap with increasing . Cu doping is shown to increase the hole concentration and narrow the band gap. The maximum dimensionless figure of merit increases from 0.03 at 400 K for to 0.2 at 500 K for . These results indicate that the semiconducting quasicrystalline approximant could be a suitable candidate as a thermoelectric material for low grade waste heat recovery.
- Received 27 March 2021
- Accepted 23 November 2021
DOI:https://doi.org/10.1103/PhysRevMaterials.5.125401
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