Enhanced Thermoelectric Properties of Ge _1.2 Mn _0.8 Te ₂ via Coalloying with PbSe and Sb

GeMnTe2 has garnered significant attention due to its stable cubic structure and favorable thermoelectric properties. Herein, guided by the distinct electronic quality factor BE, the band degeneracy of Ge1.2Mn0.8Te2 is enhanced by alloying PbSe, which not only successfully increases the thermoelectric power factor but also synergistically reduces the lattice thermal conductivity. Further alloying Sb at the Ge site optimizes the carrier concentration, thereby achieving an optimum Seebeck coefficient and power factor while simultaneously decreasing the electronic thermal conductivity. As a result, a dimensionless thermoelectric figure of merit of 1.3 at 760 K is attained in the (Ge1.05Mn0.8Sb0.15Te2)0.94(PbSe)0.06 sample, underscoring diverse benefits of PbSe and Sb coalloying in enhancing the thermoelectric performance of GeMnTe2-based materials.