Electron-hole liquid in SiC

We present calculations of the ground-state properties of the electron-hole liquid in cubic SiC. We have used the theory of the $e-h$ liquid recently developed by two of us, and have extended it to include the valence-band coupling in the zinc-blende structure when spin orbit coupling $\Delta$ is negligible. For $\Delta =0\mathrm{}$ the ground-state energy $E_G$, the Fermi energy $E_F$, and the equilibrium density $n_e$ are, respectively, 42.0 meV, 44.1 meV, and 1.65 × ${10}^{19}$ ${\mathrm{cm}}^{-3\mathrm{}}$. For $\Delta =\infty$, we obtain, instead; $E_G=39.3\mathrm{}$ meV, 40.9 meV, and 1.1 × ${10}^{19}$ ${\mathrm{cm}}^{-3\mathrm{}}$. In SiC neither of these two limits is strictly valid, but the spread in values is small and the results are in excellent agreement with recent experiments.