The physics of cuprates is strongly influenced by the dimension of the cooper-oxygen network in the considered crystals. Due to the rich manifoldness of different network geometries realized by nature, cuprates are ideal model systems for experimental and theoretical studies of low-dimensional, strongly correlated systems. The dimensionality of the considered model compounds varies between zero and three with a focus on one- and two-dimensional compounds. Starting from LDA band structure calculations, the relevant orbitals for the low-energy physics have been characterized together with a discussion of the chemical bonding in the investigated compounds. By means of a systematic approach for various compounds, the influence of particular structural components on the electronic structure could be concluded. For the undoped cuprate compounds, paramagnetic LDA band structure calculations yield a metallic groundstate instead of the experimentally observed insulating behavoir. The strong correlations were taken into account using Hubbard- or Heisenberg-like models for the investigation of the magnetic couplings in cuprates. The necessary parameters were obtained from tight-binding parameterizations of LDA band structures. Finallly, several ARPES as well as XAS measurements were interpreted. The present work shows, that the combination of experiment, LDA, and model calculations is a powerful tool for the investigation of the electronic structure of strongly correlated systems.

The physics of cuprates is strongly influenced by the dimension of the cooper-oxygen network in the considered crystals. Due to the rich manifoldness of different network geometries realized by nature, cuprates are ideal model systems for experimental and theoretical studies of low-dimensional, strongly correlated systems. The dimensionality of the considered model compounds varies between zero and three with a focus on one- and two-dimensional compounds. Starting from LDA band structure calculations, the relevant orbitals for the low-energy physics have been characterized together with a discussion of the chemical bonding in the investigated compounds. By means of a systematic approach for various compounds, the influence of particular structural components on the electronic structure could be concluded. For the undoped cuprate compounds, paramagnetic LDA band structure calculations yield a metallic groundstate instead of the experimentally observed insulating behavoir. The strong correlations were taken into account using Hubbard- or Heisenberg-like models for the investigation of the magnetic couplings in cuprates. The necessary parameters were obtained from tight-binding parameterizations of LDA band structures. Finallly, several ARPES as well as XAS measurements were interpreted. The present work shows, that the combination of experiment, LDA, and model calculations is a powerful tool for the investigation of the electronic structure of strongly correlated systems.