Electrophysical properties of solid solutions of silver in PbTe

The thermopower coefficient $\alpha_0$ and the electrical conductivity $\sigma$ of Pb$_{1-x}$Ag$_x$Te solid solutions, where $x$ = (0–0.007), are measured at $T$ = 300 K. The hole concentration $p$ is calculated. All samples are of the $p$ type. With increasing silver content, $\alpha_0$ decreases, while $p$ and $\sigma$ increase. For undoped crystals, $\alpha_0$ = 251.0 $\mu$V/K, $p$ = 1.1 $\times$ 10$^{18}$ cm$^{-3}$, and $\sigma$ = 165 $\Omega^{-1}$ cm$^{-1}$. At the silver-solubility limit for $x$ = 0.007, $\alpha_0$ = 193.8 $\mu$V/K, $p$ = 2.3 $\times$ 10$^{18}$ cm$^{-3}$, and $\sigma$ = 216 $\Omega^{-1}$ cm$^{-1}$. The hole concentration in all samples is much lower than the concentration of introduced silver atoms. The hole gas in Pb$_{1-x}$Ag$_x$Te solid solutions is weakly degenerate in the entire silver-concentration range.