We have studied temperature (1.5 K < T < 300 K) and magnetic field H < 5 T dependences of the electrical resistivity in bulk polycrystalline samples of semiconductor solid solutions (Pb_zSn_1-z)_0.8In_0.2Te with various Pb content 0.1 ≤ z ≤ 0.9. The transition to the superconducting (SC) state was observed in samples with z ≤ 0.5 at helium temperatures with the critical transition temperature increasing up to T_c = 4.1 K with an increase of the Pb content up to z = 0.5. The bulk superconductivity in solid solutions with z ≥ 0.6 was not detected at temperatures T > 1.5 K. An exponential increase of the resistivity was observed in samples (Pb_zSn_1-z)_0.8In_0.2Te with z ≥ 0.5 in the temperature range 40 K < T < 120 K. Experimental data was interpreted considering a shift of the energy position of the indium impurity band E_In in the complex valence band spectrum of (Pb_zSn_1-z)_0.8In_0.2Te with changing lead content z. The exponential increase of the resistivity with decreasing temperature in studied solid solutions is observed when an energy barrier E_a appears between valence band states and quasilocal impurity states of In. The energy barrier increases with an increase of the Pb content in compounds with 0.5 ≤ z ≤ 0.8 and reaches maximum value E_a = 9.7 meV in the solid solution with z = 0.8. The SC state at helium temperatures was observed in (Pb_zSn_1-z)_0.8In_0.2Te at z ≤ 0.4 when there is no energy barrier between zone and impurity states (i.e. the indium impurity band is located within the valence Σ-band), or at z = 0.5 when the activation energy Е_а = 0.7 meV is less than the superconducting gap Δ_S. Possible reasons for a decrease in the resistivity at T < 4.2 K in non-SC samples (Pb_zSn_1-z)_0.8In_0.2Te with z ≥ 0.6 are also discussed.

我们研究了温度 (1.5 K < T < 300 K) 和磁场H < 5 T 对半导体固溶体 (Pb _z Sn _1-z ) _0.8 In _0.2 Te 各种 Pb 含量 0.1 ≤ z ≤ 0.9。在氦温度下z ≤ 0.5的样品中观察到向超导 (SC) 状态的转变 ，随着 Pb 含量增加到z  = 0.5 ，临界转变温度增加到T _{c = 4.1 K。}具有z的固溶体中的体积超导性在温度T > 1.5 K时未检测到 ≥ 0.6 。在 40 K < T < 120 K的温度范围内，在z ≥ 0.5 的样品 (Pb _z Sn _1-z ) _0.8 In _0.2 Te中观察到电阻率呈指数增加。实验数据被解释为考虑到 (Pb _z Sn _1-z ) _0.8 In _0.2 Te的复价带光谱中铟杂质带E _In的能量位置随铅含量z的变化而变化. 当能量势垒E _a出现在 In 的价带态和准局域杂质态之间时，观察到所研究的固溶体中电阻率随温度降低呈指数增加。在 0.5 ≤ z ≤ 0.8的化合物中，能垒随着 Pb 含量的增加而增加，在z = 0.8 的固溶体中达到最大值E _a = 9.7 meV  。氦温度下的 SC 状态在 (Pb _z Sn _1-z ) _0.8 In _0.2 Te 在z ≤ 0.4 时观察到，此时区域和杂质状态之间没有能垒（即铟杂质带位于价带 Σ 带内），或者 当激活能Е _а  = 0.7 meV 小于超导间隙_ΔS时， z = 0.5 。还讨论了非 SC 样品 (Pb _z Sn _1-z ) _0.8 In _0.2 Te 与z ≥ 0.6 中T < 4.2 K 时电阻率降低的可能原因。