Galvanomagnetic and thermomagnetic properties of AgSbTe$_{2}$

We report here data on the electrical resistivity, magnetoresistance, Hall effect, thermoelectric power, magneto-Seebeck and transverse Nernst-Ettingshausen coefficients of high-quality crystals of AgSbTe$_{2}$, measured from 77 to 400 K in magnetic fields up to 2 Tesla. Thermal conductivity data are also reported in samples with a much higher carrier concentration than those used in our other work.$^{1}$ From an analysis of these data, we conclude AgSbTe$_{2}$ to be a very narrow-gap semiconductor (Eg$\approx $ 7.6$\pm $3 meV) with $\sim $5x10$^{19}$ cm$^{-3}$ holes in a valence band with a high density of states and thermally excited $\sim $10$^{17}$ cm$^{-3}$ high-mobility (2,200 cm$^{2}$/Vs) electrons at 300 K. The estimated hole density-of-states effective masses, including Fermi pocket degeneracy, is 2.5$\pm $0.5 free electron masses; the electron mass is about two orders of magnitude smaller, but the exact value cannot be resolved. The lattice term dominates the thermal conductivity, $^{1}$ and the electronic contribution in samples with both electrons and holes present is in turn dominated the ambipolar term. The low thermal conductivity and very large hole mass of AgSbTe$_{2}$ make it a most promising p-type thermoelectric material. [1] Lattice thermal conductivity of AgSbTe$_{2}$, D. T. Morelli, V. Jovovic, S. J. Tiagarajan, and J. P. Heremans, Abstract reported here.