Chemical characterization of an alkali-like silicon cage superatom:
a promising building block for nanodevices and catalyst

We have carefully deposited an alkali-like superatom consisting of a Ta-encapsulating Si₁₆ cage, Ta@Si₁₆, onto an inert graphite substrate, and have evaluated its chemical property and robustness by x-ray photoelectron spectroscopy. The result shows that both Ta and Si atoms consisting of the superatom have been well modelled with a single chemical component, revealing the formation of a symmetric Si cage around the Ta atom in the deposited nanoclusters. The deposited Ta@Si₁₆ shows extreme stability for heating up to 700 K and oxygen exposure. The chemical robustness of Ta@Si₁₆ nanoclusters shows the promising possibility of applying Ta@Si₁₆ as a building block to construct novel nanodevices and catalyst utilizing their unique properties as superatom chemistry.