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HL: Fachverband Halbleiterphysik
HL 40: Thermal, acoustic and transport properties
HL 40.4: Vortrag
Mittwoch, 18. März 2020, 10:15–10:30, POT 151
Transport properties of natural and synthetic FeAsxS2−x (0 ≤ x ≤ 0.01) pyrites — •Esteban Zuñiga-Puelles1,2, Raul Cardoso-Gil2, Matej Bobnar2, Igor Veremchuk2, Cameliu Himcinschi1, Jens Kortus1, and Roman Gumeniuk1 — 1TU Bergakademie Freiberg, Freiberg, Germany — 2Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden
Synthetic polycrystalline and natural (Schönbrunn mine, Saxony, Germany) pyrites show comparable electrical resistivities (corresponding to the energy gaps ∼ 0.7-0.9 eV) and Seebeck coefficients (-350 to -400 µV K−1 at 600 K). On the other hand, their thermal conductivities are similar (i.e. nearly temperature independent ∼40-20 W m−1 K−1) above 200 K. Below this temperature natural pyrite reveal a strong and well pronounced maximum, which became strongly reduced in synthetic samples. Such an effect is caused by much smaller grain size (≤ 100 µm) in synthetic FeS2, which results in additional scattering mechanisms (i.e. on point defect and/or grain boundaries). Therefore, mineral from Schönbrunn is further considered as a model system.
Interestingly, electrical transport properties of pyrites from other mines in Saxony varies from metallic (n-type conductivity) to semiconducting (p-type conductors). To shed light on such a behavior, FeAsxS2−x (0 ≤ x ≤ 0.01) compounds were synthesized. The increase of As-content x in this system results in a decrease of the electrical resistivity as well as in the shift of the type of conducting mechanism towards hole-like one.