EFFECT OF HIGH-PRESSURE ON THE ELECTRICAL-CONDUCTIVITY OF TLINX2 (X=SE,TE) LAYERED SEMICONDUCTORS

The dc electrical conductivity of TlInX2 (X = Se, Te) single crystals, parallel and perpendicular to the (001) c-axis is studied under high quasi-hydrostatic pressure up to 7.0 GPa, at room temperature. Conduct ivity measurements parallel to the c-axis are carried out at high pres sures and down to liquid nitrogen temperatures. These materials show c ontinuous metallization under pressure. Both compounds have almost the same pressure coefficient of the electrical activation energy paralle l to the c-axis, d(DELTAE(parallel-to))/dP = - 2.9 x 10(-10) eV/Pa, wh ich results from the narrowing of the band gap under pressure. The res ults are discussed in the light of the band structure of these compoun ds.