Green’s-function approach to linear response in solids
Stefano Baroni, Paolo Giannozzi, Andrea Testa
Abstract
We present a new scheme to study the linear response of crystals which combines the advantages of the dielectric-matrix and supercell (``direct'') approaches yet avoids many of their drawbacks. The numerical complexity of the algorithm is of the same order as that of a self-consistent calculation for the unperturbed system. The method is not restricted to local perturbations as the dielectric-matrix one nor to short wavelengths as the direct one. As an application, we calculate the long-wavelength optical phonons in Si and GaAs, both transverse and longitudinal, using norm-conserving pseudopotentials, and without any use of supercells.
Topics & Concepts
WavelengthDielectric responseDielectricDielectric functionPhysicsMatrix (chemical analysis)Order (exchange)Function (biology)OpticsCondensed matter physicsComputational physicsStatistical physicsMaterials scienceQuantum mechanicsEvolutionary biologyBiologyEconomicsFinanceComposite materialSilicon Nanostructures and PhotoluminescencePhotonic and Optical DevicesPhotonic Crystals and Applications