ANOMALOUS RESISTIVITY NEAR THE FERROELECTRIC PHASE-TRANSITION IN (PB,GE,SN)TE ALLOY SEMICONDUCTORS

The phase transition in Pb1-xGexTe (0<x<0.10) and Pb1-xSnxTe has been systematically investigated by the electrical-transport method. The composition dependence of the transition temperature in Pb1-xGexTe determined from an electrical resistivity anomaly is in good agreement with other experiments. We found that the resistivity-anomaly peak position increases with a reduction of the anomaly under a strong magnetic field in Pb1-xGexTe (x=0.01,0.015) and Pb1-xSnxTe (x=0.40). The magnetic field dependence is tentatively explained by an interband-electron TO-phonon coupling model, taking into account the phonon anharmonicity. © 1979 The American Physical Society.