Calculation of the nonlinear susceptibility for optical second-harmonic generation in III-V semiconductors

We calculate both linear and nonlinear optical response in the static limit for AlP, AlAs, GaP, and GaAs in the local-density approximation with and without a scissors operator, including local-field effects. The calculation agrees with the measurement of Levine and Bethea to within 15%. The derivatives d lnχ⁽²⁾/d lna, for lattice constant a, are predicted to be from 1.7 to 6.6 times the values obtainable from existing models. The calculated static dielectric constants ε_∞ are within 2% of measured values; calculated results for d lnε_∞/d lna are also presented. The scissors operator alters ε_∞ up to 25% but alters χ⁽²⁾ by a factor of 2.