Coexistence of Electron-Hole Gas and Liquid in Ge

The electron-hole gas, in equilibrium with the electron-hole liquid, has been directly observed in Ge by observation of a luminescence feature. Parameters of the coexistence curve between the two phases are determined to be $T_c=7.0\mathrm{}\pm 0.1$ K and $n_c=(8.9\mathrm{}\pm 0.5)\times {10}^{16}$ Information concerning the transition between the electron-hole-gas phase and bound excitons is also obtained.