Charge transfer, insulating character

The most remarkable property, worthy of mention here, is that an enormous gain of conductivity is realized in such mixtures in comparison with the insulating character of the two individual components. This implies a significant charge mobility in addition to the strong charge-transfer ef-... 

This first chapter summarizes the main bulk characteristics of insulating oxides, as a prerequisite to the study of surfaces. The foundations of the classical models of cohesion are first recapitulated, and the distinction between charge-transfer oxides and correlated oxides is subsequently established. Restricting ourselves to the first family, which is the subject of this book, we analyse the mixed iono-covalent character of the anion-cation bonding and the peculiarities of the bulk electronic structure. This presentation will allow us to introduce various theoretical and experimental methods - for example, the most common techniques of band structure calculation - as well as some models - the partial charge model, the alternating lattice model - which will be used in the following chapters. 

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