A modeling approach for new CrSi2 based alloys: application to metastable Cr1-xZrxSi2 as a potential thermoelectric material

Increasing the power factor (S2σ) of CrSi2 is considered as a promising way to improve its thermoelectric efficiency and can be done by modifying its electronic structure. In this work, p-type doping has been investigated with heavy elements such as Ti, V, Zr, Nb, Hf and Ta selected by first-principles calculations. At first, we have theoretically examined the solubility of the selected elements on the Cr site to evaluate the existence of a solid solution domain. Previous study has shown that Ti doping improved the power factor of CrSi2. Based on the similarity of the electronic structure of Ti and Zr, we pursue our investigation by studying Cr1-xZrxSi2 alloys. A discrepancy is observed between theoretical and experimental data which highlights the importance of the synthesis technique, notably in order to stabilize metastable alloys. We have observed a significant enhancement of S2σ by a factor 1.6 between pure CrSi2 and Cr0.98Zr0.02Si2.