Effect of non-stoichiometry on the thermal and electrical properties of polycrystalline PtSb2 at low temperature

In narrow bandgap materials non-stoichiometry can dramatically change the measured electrical and thermal properties below room temperature. The work here attempts to examine the effects of non-stoichiometry on the low temperature properties of polycrystalline PtSb2. It was found that at antimony deficiencies of only 1% a change in the sign of the Seebeck coefficient was observed from 80 to 120 K. Further reduction of the antimony content resulted in a negative Seebeck for all temperatures measured. Antimony excess was found to retain positive values in the Seebeck coefficient, but with a reduction in the magnitude. The electrical resistivity was found to vary largely at low temperature, however converged to similar values at room temperature. These results show the importance of stoichiometry in narrow bandgap materials at low temperature.