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.
|Titolo:||Green’s-function approach to linear response in solids|
|Autori:||Baroni, S.; Giannozzi, P.; Testa, A.|
|Data di pubblicazione:||1987|
|Digital Object Identifier (DOI):||10.1103/PhysRevLett.58.1861|
|Appare nelle tipologie:||1.1 Journal article|