The response of extended systems to electrostatic fields

The response to electrostatic fields by finite systems, which contain a large central region of chemically identical building blocks, is shown not to depend on the boundaries of the system. Consequently, we can determine this response from that of the corresponding infinite periodic system and a vector potential theoretical-computational approach is presented for doing so. Both the electronic and structural response can be obtained with our approach. In many cases, neglecting the structural response is a poor approximation. To illustrate the performance of our treatment, extensive calculations have been carried out for simple model systems. Selected results are reported. Key words: polarization, extended systems, electrostatic fields, structural properties, electronic properties. On demontre que, pour des systemes finis contenant une grande region de blocs chimiquement identiques, la reponse a des champs electrostatiques ne depend pas des limites du systeme. En consequence, on peut determiner cette reponse a partir des systemes infinis correspondants et on presente une approche par calculs theoriques des potentiels vectoriels qui permet d'y arriver. Avec notre approche, il est possible d'obtenir aussi bien la reponse electronique que structurelle. Dans plusieurs cas, si on neglige la reponse structurelle, on obtient une mauvaise approximation. Afin d'illustrer la performance de notre traitement, on a effectue des calculs extensifs de systemes modeles simples. On rapporte des resultats choisis. Mots-cles : polarisation, systemes etendus, champs electrostatiques, proprietes structurelles, proprietes electroniques.
[Traduit par la Redaction] Introduction With this contribution, we want to honor Tom Ziegler on the occasion of his 65th birthday. It happens that Tom Ziegler shares a number of [...]