Anomalous resistivity near the ferroelectric phase transition in (Pb, Ge, Sn)Te alloy semiconductors

Abstract

The phase transition in ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}\mathrm{Te}$ ($0<x<0.10$) and ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ has been systematically investigated by the electrical-transport method. The composition dependence of the transition temperature in ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}\mathrm{Te}$ 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 ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}\mathrm{Te}$ ($x=0.01,0.015$) and ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ ($x=0.40$). The magnetic field dependence is tentatively explained by an interband-electron---TO-phonon coupling model, taking into account the phonon anharmonicity.