Surface Structure of Electron-Hole Droplets

We consider the surfaces of the condensed phase of excitons in semiconductors, the electron-hole liquid (EHL). By using the theory of the inhomogeneous electron gas and a variational technique we estimate the surface tension for the EHL in Ge to be ${10}^{-4\mathrm{}}$ erg/${\mathrm{cm}}^2$; the carrier density in the surface region varies on a scale of ≈ 50 Å. We suggest an experiment to measure the surface tension of the EHL.