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Title: Electronic structure study of copper-containing perovskites
Author: Michel, M. R.
ISNI:       0000 0004 2728 0161
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2010
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This thesis concerns the computational study of copper containing perovskites using electronic structure methods. We discuss an extensive set of results obtained using hybrid exchange functionals within Density Functional Theory (DFT), in which we vary systematically the amount of exact (Hartree-Fock, HF) exchange employed. The method has enabled us to obtain accurate results on a range of systems, particularly in materials containing strongly correlated ions, such as Cu2+. This is possible because the HF exchange corrects, at least qualitatively, the spurious self-interaction error present in DFT. The materials investigated include two families of perovskite-structured oxides, of potential interest for technological applications due to the very large dielectric constant or for Multi-Ferroic behaviour. The latter materials exhibit simultaneously ferroelectric and ferromagnetic properties, a rare combination, which is however highly desirable for memory device applications. The results obtained using hybrid exchange functionals are highly encouraging. Initial studies were made on bulk materials such as CaCu3Ti4O12 (CCTO) which is well characterised by experiment. The inclusion of HF exchange improved, in a systematic way, both structural and electronic results with respect to experiment. The confidence gained in the study of known compounds has enabled us to explore new compositions predictively. Interesting results have been obtained, and we have been able to identify new materials of potential interest, which represent clear new targets for future experimental studies.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available