Perovskite band structure, electronic

We analyse how the electronic properties of perovskite-structured materials change as a function of the mixing parameter a by making use of the model TB Hamiltonian, as detailed earlier. In particular, we examine the calculated band-structure of the materials along the T-X direction of reciprocal space, from which we can evaluate the effective parameters Aa and p. 

As most perovskite studies have focussed on d-electron-containing oxides, these will mainly feature here. The band structures of these compounds can be calculated... 

Figure 6.13 Electronic band structure of the cubic perovskite KTaOs as calculated using LMTO-ASA calculations. The Fermi level is set to zero energy and marked with light grey. Fatband hatching indicates the contributions of specific orbitals to the electronic structure. The upper plot shows the Ta 5d t2g (dark grey), Ta 5d Cg (thick line) and K 4s (dark grey) fatbands, while the lower plot shows the O 2p (dark grey) and O 2s (thick line) fatbands...

Tlie plienomenon of half-metallicity has gained much interest in order to understand the unusual band structures in various classes of materials and their potential applications in future electronic devices. For example, zinc blend pnictides and chalcogenides e.g. CrAs) are another class of non-oxide materials (apart from Heuslers) in addition to the many oxide classes that are potentially half-metallic materials. Alkali metal doped rare earth oxomanganates, (REi- A MnOs), rutile-Cr02, spinel-Fe304 and Sr2peMo06 double perovskite oxide are examples of important half-metallic oxides. 

Due to its metallic and FM property, similar to double perovskites (see later), Cr02 is of great interest to material scientists and physicists. A computed band structure of Cr02 is shown in Figure 5.6. The Fermi level crosses the majority-spin band while it lies in a gap of the minority-spin density of states (DOS). Therefore, Cr02 is half-metallic on the basis of electronic structure calculations. The same band structure has been reproduced by several groups since it was first demonstrated by... 

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