Computational Screening of Two‐Dimensional Sc 2 GeX 2 (X = Cl, Br, I) for Thermoelectric Applications

ABSTRACT This study examines the electrical, structural, and thermoelectric properties of newly constructed germanide halides of the rare earth metal Scandium, with chemical formula Sc 2 GeX 2 (where X = Cl, Br, or I). These materials exhibit semiconductor behavior with an indirect narrow bandgap estimated to be 0.14 eV for Sc 2 GeBr 2 , and 0.24 eV for Sc 2 GeI 2 . The thermoelectric properties are analyzed using the first principles method in conjunction with the Boltzmann transport equations (BTE). Two out of three materials of a Scandium germanide halogen series are mechanically and dynamically stable. The Figure of Merit (ZT) is determined by evaluating and integrating thermoelectric coefficients such as thermal conductivity, electrical conductivity, and Seebeck coefficient. The lattice thermal conductivity values for these materials are computed for Sc 2 GeI 2 , exhibiting the lowest value of 1.32 Wm −1 K −1 and Sc 2 GeBr 2 with lowest value of 2.96 Wm −1 K −1 at 300 K. The highest figure of merit (ZT) between these novel materials is 0.54 for Sc 2 GeI 2 with Seebeck coefficient of 349.98 µV K −1 , electrical conductivity 13.97 × 10 5 S m −1 and electronic thermal conductivity 9.66 Wm −1 K −1 whereas Sc 2 GeBr 2 shows lower value of figure of merit, i.e., 0.40. These results suggest that these materials can be considered as promising candidates for energy harvesting in thermoelectric applications.