Effect of Hydrostatic Pressure on the Static Permittivity of Germanium

The dependence of the static permittivity of single-crystal germanium on hydrostatic pressure up to P ≈ 7.4 GPa is studied experimentally. As the pressure is increased to P ≈ 4 GPa, the permittivity of Ge decreases by a factor of ~13 to ε = 1.22. As the pressure is increased further to P ≈ 7 GPa, a moderate increase in ε to the initial value is observed. In the range 7–7.4 GPa, the permittivity increases to a value larger than 1000. The experimental dependences obtained in the study substantially differ from the previously known dependences.