Multi-gap absorption in CaCu${}_3$Ti${}_4$O${}_{12}$ and the predictivity of ab initio methods

Abstract

We report the electronic properties of the quadruple perovskite CaCu${}_3$Ti${}_4$O${}_{12}$ as obtained via several density-functional based methods, and propose a new interpretation of optical experiments to the effect that four distinct transitions (centered around 0.7, 1.5, 2.5, and 3.5 eV) contribute to the spectrum. The comparison with experiment is satisfactory, especially after we account for the effects of spin disorder, which does not close the fundamental gap but suppresses the transition intensity. We find that some of the methods we employ tend to overestimate considerably the gaps for standard values of the respective adjustable parameters.

10 pages, 13 figures, 1 table

References in corpus (4)

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• Onset of Magnetic Order in Strongly-Correlated Systems from ab initio Electronic Structure Calculations: Application to Transition Metal Oxides
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