Ab initio calculation of band-gap renormalization in highly excited GaAs -: art. no. 205204

We present ab initio quasiparticle self-energy calculations in crystalline GaAs for cases of intense electronic excitation (similar to10% of valence electrons excited into conduction band), relevant for high-intensity ultrashort pulsed laser experiments. Calculations are performed using an out-of-equilibrium generalization of the GW approximation based on the Keldysh Green's function approach. Our results indicate that while the quasiparticle band gap is a sensitive function of the amount of excitation, it is not possible to induce complete band-gap closure in this system by purely electronic means.