Resistivity Anomalies in Pb1-xGexTe at Low Temperatures

Electrical measurements of n- and p-Pb 1- x Ge x Te have been made between 4.2 K and 300 K. Below 40 K, resistivity exhibits anomalous behaviours similar to the Kondo effect in a dilute magnetic alloy. The anomaly is strongly correlated with the phase transition temperature. The formation of the pseudo-spins and the effect of their ordering on the resistivity anomaly are discussed.