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arXiv · 1303.4502

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

H. J. Im·M. Tsunekawa·T. Sakurada·M. Iwataki·K. Kawata·T. Watanabe·K. Takegahara·H. Miyazaki·M. Matsunami·T. Hajiri·S. Kimura
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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.

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H. J. Im, M. Tsunekawa, T. Sakurada, M. Iwataki, K. Kawata, T. Watanabe, K. Takegahara, H. Miyazaki, M. Matsunami, T. Hajiri, S. Kimura. 2013-06-25. Strong Correlation Effects of A-site Ordered Perovskite CaCu3Ti4O12 revealed by Angle-Resolved Photoemission Spectroscopy. https://doi.org/10.1103/physrevb.88.205133

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