PRESSURE-INDUCED TRANSITION TO GAPLESS STATE IN In-DOPED Pb1 - xSnxTe ALLOY.

An investigation was made of the galvanomagnetic and oscillatory effects in Pb//0//. //7//8Sn//0//. //2//2Te containing 0. 5 at. % In subjected to hydrostatic pressures which resulted in transition to the gapless state. The measurements were carried out under pressures up to 16 kbar in magnetic fields up to 40 kOe at temperatures of 4. 2 and 300 degree K. The carrier density and the extremal sections of the Fermi surface increased under the pressure and passed through a maximum in the region of the transition to the gapless state at P approximately equals P//i. The results obtained were used to plot a diagram showing the pressure-induced shifts of the energy levels and to calculate the pressure coefficient of the forbidden bandwidth.