PES and XAS Study on Electronic Structures of Multiferroic RMnO${}_3$ (R=Y, Er)

Abstract

Electronic structures of multiferroic RMnO${}_3$ (R=Y, Er) have been investigated by employing photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). We have found that Mn ions in RMnO${}_3$ are in the trivalent high-spin state with the total spin of S=2. The occupied Mn ($d_{xz}-d_{yz}$) states lie deep below ${\mathrm{E}}_{\mathrm{F}}$, while the occupied Mn ($d_{xy}-d_{x^2-y^2}$) states overlap very much with the O $2p$ states. It is observed that the PES spectral intensity of Mn 3d states is negligible above the occupied O $2p$ bands, suggesting that YMnO${}_3$ is likely to be a charge-transfer insulator. The Mn $d_{3z^2-r^2}$ state is mostly unoccupied in the ferroelectric phase of YMnO${}_3$.

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