Strong Correlation Effects of A-site Ordered Perovskite CaCu3Ti4O12 revealed by Angle-Resolved Photoemission Spectroscopy

Abstract

We report angle-resolved photoemission spectroscopy (ARPES) results of A-site ordered perovskite CaCu${}_3$Ti${}_4$O${}_{12}$. We have observed the clear band dispersions, which are shifted to the higher energy by 1.7 eV and show the band narrowing around 2 eV in comparison with the local density approximation calculations. In addition, the high energy multiplet structures of Cu 3$d^8$ final-states have been found around 8 - 13 eV. These results reveal that CaCu${}_3$Ti${}_4$O${}_{12}$ is a Mott-type insulator caused by the strong correlation effects of the Cu 3$d$ electrons well hybridized with O 2$p$ states. Unexpectedly, there exist a very small spectral weight at the Fermi level in the insulator phase, indicating the existence of isolated metallic states.

5 pages, 5 figures

References in corpus (1)

• Correlation effects in CaCu3Ru4O12

Cited by in corpus (3)

• Electronic structure of Mott-insulator CaCu3Ti4O12: Photoemission and inverse photoemission study
• Temperature dependence of the electronic structure of A-site ordered perovskite CaCu${}_3$Ti${}_4$O${}_{12}$: Angle-integrated and -resolved photoemission studies
• Variation of strong correlation effects in A-site ordered perovskites CaCu3Ti4-xRuxO12: Photoemission and inverse photoemission studies