Experimental Evidence for Phase Separation of a Two-Component Electron-Hole Liquid in 〈111〉 -Stressed Ge

Measurements of time-resolved luminescence spectra of electron-hole liquid in Ge under $〈111〉$ uniaxial stress are reported. It is shown that these spectra present strong evidence that a novel phase separation recently predicted theoretically for this system does indeed occur. The critical ratio ${x}_{c}$ of the number of hot electrons to that of cold electrons below which the phase separation occurs is found to be 0.63 for a stress of 6.8 kg/${\mathrm{mm}}^{2}$.