Electrical, thermal, and thermomagnetic transport properties of the chalcopyrite compound CdSnAs₂

In the ongoing effort to identify new semiconducting materials with improved thermoelectric performance, compounds having the chalcopyrite structure with general formula II-IV-V₂ are recently receiving significant attention. In the present work, we report the results of a study of the galvanomagnetic, thermomagnetic, and thermal transport properties of CdSnAs₂ with the chalcopyrite structure. Temperature dependent transport measurements on nominally undoped polycrystalline CdSnAs₂ indicate n-type semiconducting behavior with a relatively high thermoelectric power factor. This is correlated with a very high Hall mobility greater than 1700 cm² V^-1 s^-1 at 300 K that increases with temperature, in contrast to the behavior for typical semiconductors. Using the “method of four coefficients,” in which the electrical resistivity, Seebeck coefficient, Hall coefficient, and Nernst coefficient are measured on a single sample, we glean insights into the underlying mechanisms for this behavior and its relationship to the effective mass and dominant charge carrier scattering mechanism in this material. This work contributes to the fundamental understanding of chalcopyrite-based materials, providing guidance for investigations into altering/improving their properties for thermoelectric applications.