HIGH-PRESSURE ABSORPTION AND RAMAN-STUDY OF THE QUASI-LINEAR COMPOUNDCSCUS6

We report the results of a combined high pressure absorption and Raman study on CsCuS6. The indirect band gap, E(g), at about 2eV shifts to lower energy with increasing pressure (55 meV/GPa). The pressure shift is approximately linear up to 17 GPa, the maximum pressure of our stu dy. An extrapolation yields a band closure pressure of about 37 GPa. T he Raman spectra of the internal modes are closely related to those of heterocyclic sulphur molecules.