We investigated the local electronic structures of a molecularly thin ferromagnetic Ti0.8 Co0.2 O2 nanosheet by means of x-ray nanospectroscopy with spectroscopic photoemission and low energy electron microscopy. By analyzing the Co 2p x-ray absorption and photoemission spectra, the chemical state of doped Co ions in individual Ti0.8 Co0.2 O2 nanosheet was found to be Co2+ low-spin state, which is consistent with previous magnetization data and first-principles calculation [M. Osada, Phys. Rev. B 73, 153301 (2006)]. Furthermore, we employed photoelectron emission microscopy to image the variation in chemical states in Ti0.8 Co0.2 O2 nanosheets with different stacking structures and clarified the identical Co2+ low-spin state in monolayer and overlapped cases.
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