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Some remarks on the theory of the dielectric response of crystals and on the lorentz‐lorenz formula
Author(s) -
Fiorino E.,
Del Sole K.
Publication year - 1983
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221190136
Subject(s) - polarizability , lorentz transformation , dipole , dielectric , condensed matter physics , crystal (programming language) , physics , hyperboloid model , mathematics , quantum mechanics , molecule , computer science , programming language , minkowski space
An investigation is made of the macroscopic dielectric function of a model insulator including local field effects and treating exchange by (i) the many‐body perturbation technique, (ii) the mean field, and (iii) excitonic approximations. The different methods yield similar results, showing the reliability of approximations (ii) and (ii) in most cases. Also the validity of the Lorentz‐Lorenz formula is discussed, showing that it is always valid in cubic crystals, if the “atomic” polarizability is suitably defined as the limit of the crystal polarizability for vanishing dipole—dipole interaction.