  The dc-current-induced optical second-harmonic generation is observed at the
surface of centrosymmetric single crystal of Si. Surface dc-current with
density up to $\textit{j}_{max} \sim 10^{3}$ A/cm$^{2}$ results in break of
inversion symmetry of Si and induces optical second-harmonic generation with
intensity that corresponds to the appearance of dipole second-order
susceptibility $\chi^{(2)d}(j_{max})\sim 3 \cdot 10^{-15}$m/V.
