High pressure phase transition in PbSnTe

The high pressure structural phase transition in the alloy series Pb_{1 ? x}Sn_xTe has been investigated using resistivity and Hall coefficient measurements. With increasing of tin content the critical pressure decreases linearly and the phase transition becomes less drastic. The anomalous behavior of the resistivity in the phase transition region is explained by band structure changes. It is suggested that the high pressure phase transition in Pb_{1 ? x}Sn_xTe is a metallic-covalent transition.