Thermomagnetic and Galvanomagnetic properties of Tl doped PbTe-PbS*

It was recently shown that p-type PbTe-Tl has a significant increase in zT over that PbTe:Na\footnote{\textit{Science} 25 July 2008:Vol. 321. pp. 554 - 557} due to an increase in power factor. Also, a large increase in zT in n-type PbTe was reported when alloyed with PbS due to the reduction in thermal conductivity.\footnote{\textit{J. Am. Chem. Soc.}, 2007, 129 (31), pp 9780--9788} This work is an attempt at combining those two effects to further increase zT. We synthesis Pb$_{0.98}$Tl$_{0.02}$Te$_{1-x}$S$_{x}$ with 4{\%}$<$x$<$16{\%} and report here on measurements of thermopower, electrical resistivity, thermal conductivity, Hall and Nernst coefficients from 80-600K, and report zT. Initial thermopower and carrier density measurements indicate that Tl remains resonant in PbTe-PbS.