Unlocking the thermoelectric potential of the Ca <sub>14</sub> AlSb <sub>11</sub> structure type
Andrew P. Justl, Francesco Ricci, Andrew Pike, Giacomo Cerretti, Sabah K. Bux, Geoffroy Hautier, Susan M. Kauzlarich
Abstract
Yb 14 MnSb 11 and Yb 14 MgSb 11 are among the best p-type high-temperature (>1200 K) thermoelectric materials, yet other compounds of this Ca 14 AlSb 11 structure type have not matched their stability and efficiency. First-principles computations show that the features in the electronic structures that have been identified to lead to high thermoelectric performances are present in Yb 14 ZnSb 11 , which has been presumed to be a poor thermoelectric material. We show that the previously reported low power factor of Yb 14 ZnSb 11 is not intrinsic and is due to the presence of a Yb 9 Zn 4+ x Sb 9 impurity uniquely present in the Zn system. Phase-pure Yb 14 ZnSb 11 synthesized through a route avoiding the impurity formation reveals its exceptional high-temperature thermoelectric properties, reaching a peak zT of 1.2 at 1175 K. Beyond Yb 14 ZnSb 11 , the favorable band structure features for thermoelectric performance are universal among the Ca 14 AlSb 11 structure type, opening the possibility for high-performance thermoelectric materials.