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The perovskite family of oxides includes a vast array of insulators, metals, and semiconductors. Current intense scientific interest stems from the large number of diverse phenomena exhibited by these materials including pseudo two-dimensional electronic energy bands, high temperature superconductivity, metal-insulator transitions, piezoelectricity, magnetism, photochromic, and catalytic activity. This book is the first text devoted to a comprehensive theory of the solid-state properties of these fascinating materials. The text includes complete descriptions of the important energy bands, photoemission, surface states, and the chapter on high-temperature superconductors explores the electronic states in typical copper-oxide materials. Theoretical results are compared to experiment and discussed throughout the book. With problem sets included, this is a unified, logical treatment of fundamental perovskite solid-state chemistry which will appeal to graduate students and researchers alike.

The adsorption profiles and electronic structures of Pt n ͑n =1-4͒ clusters on stoichiometric, reduced and reconstructed rutile TiO 2 ͑110͒ surfaces were systematically studied using on site d-d Coulomb interaction corrected hybrid density-functional-theory ͑DFT͒ calculations. The atomic structure of small Pt cluster adsorbates mainly depends on the stoichiometry of the corresponding titania support. The cluster shapes on the bulk terminated ideal surface look like their gas phase low-energy structures. However, for instance, they get significantly distorted on the reduced surfaces with increasing oxygen vacancies. On nonstoichiometric surfaces, Pt-Ti coordination becomes dominant in the determination of the adsorption geometries. The electronic structure of Pt n / TiO 2 ͑110͒ systems cannot be correctly described by pure DFT methods, particularly for nonstoichiometric cases due to the inappropriate treatment of the correlation for d electrons. We performed DFT+ U calculations to give a reasonable description of the reconstructed rutile ͑110͒ surface. Pt clusters induce local surface relaxations that influence band edges of titania support and bring a number of band-gap states depending on the cluster size. Significant band gap narrowing occurs upon Pt n -surface interaction due to adsorbate driven states on the bulk terminated and reduced surfaces. On the other hand, they give rise to a band-gap widening associated to partial reoxidation of the reconstructed surface. No metallization arises even for Pt 4 on rutile.

The structural profiles and electronic properties of pentacene (C 22 H 14 ) multilayers on Ag(111) surface has been studied within the density functional theory (DFT) framework. We have performed first-principle total energy calculations based on the projector augmented wave (PAW) method to investigate the initial growth patterns of pentacene (Pn) on Ag(111) surface.In its bulk phase, pentacene crystallizes with a triclinic symmetry while a thin film phase having an orthorhombic unit cell is energetically less favorable by 0.12 eV/cell. Pentacene prefers to stay planar on Ag(111) surface and aligns perfectly along silver rows without any molecular deformation at a height of 3.9 Å. At one monolayer (ML) coverage the separation between the molecular layer and the surface plane extends to 4.1 Å due to intermolecular interactions weakening surface-pentacene attraction. While the first ML remains flat, the molecules on a second full pentacene layer deposited on the surface rearrange so that they become skewed with respect to each other. This adsorption mode is energetically more preferable than the one for which the molecules form a flat pentacene layer by an energy difference similar to that obtained for bulk and thin film phases. Moreover, as new layers added, pentacenes assemble to maintain this tilting for 3 and 4 ML similar to its bulk phase while the contact layer always remains planar. Therefore, our calculations indicate bulk-like initial stages for the growth pattern.