The dielectric function in p-type III-V semiconductors

The dependences on frequency, wavevector, temperature, and carrier damping of the dielectric functions of p-type semiconductors with zinc-blende or diamond structure are calculated. Analytic expressions are derived in the random-phase approximation, and finite-lifetime effects are included in a relaxation time approximation. The ranges of dominant intraband and interband transitions are discussed for the example of GaAs. Interband transitions are very significant at low temperatures and small wavevectors. The theoretical results are compared with light scattering experiments on p-GaAs.