PRESSURE-DEPENDENCE OF THE LOWEST DIRECT ABSORPTION-EDGE OF ZNTE

The dependence of the lowest direct absorption gap E//0 of ZnTe on hydrostatic pressure has been measured at room temperature with a diamond anvil cell for pressures up to the second phase transition (11. 9 plus or minus 0. 3 Gpa). The energy gap E//0 (eV) equals 2. 27 plus 10. 4 multiplied by (times) 10** minus **2 multiplied by (times) P minus 28 multiplied by (times) 10** minus **4 multiplied by (times) P**2 (P in GPa) exhibits a sublinear dependence on P up to the first phase transition at 9. 4 plus 0. 3 GPa. However, if the gap is plotted as a function of the relative change of lattice constant ( minus DELTA a/a//0) it shows, within error, a linearity with E//0 (eV) equals 2. 266 plus 16. 2 ( minus DELTA a/a//0). The experimental results are compared to theoretical calculations based on a local empirical pseudopotential and with recently published ab initio LMTO calculations.