Ab initiostudy of the nonlinear optics of III-V semiconductors in the terahertz regime

Eric Roman, Jonathan R. Yates, Marek Veithen, David Vanderbilt, Ivo Souza
2006 Physical Review B  
We compute from first principles the infrared dispersion of the nonlinear susceptibility $\chi^{(2)}$ in zincblende semiconductors. At terahertz frequencies the nonlinear susceptibility depends not only on the purely electronic response $\chi^{(2)}_{\infty}$, but also on three other parameters $C_1$, $C_2$ and $C_3$ describing the contributions from ionic motion. They relate to the TO Raman polarizability, the second-order displacement-induced dielectric polarization, and the third-order
more » ... third-order lattice potential. Contrary to previous theory, we find that mechanical anharmonicity ($C_3$) dominates over electrical anharmonicity ($C_2$), which is consistent with recent experiments on GaAs. We predict that the sharp minimum in the intensity of second-harmonic generation recently observed for GaAs between $\omega_{\rm TO}/2$ and $\omega_{\rm TO}$ does not occur for several other III-V compounds.
doi:10.1103/physrevb.74.245204 fatcat:xnngquy2gvcbddctf2onweorkm