日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Novel materials can be created in regular nanospaces of zeolite crystals by the loading of guest materials. In the case of the loading of alkali metals, s-electrons of guest atoms are shared with alkali cations of zeolites, and form clusters with new quantum electronic states. The successive occupation of s-electrons in clusters is compared to the superatom states with the nanometer size. The regular array of these clusters exhibits novel electronic properties, such as ferromagnetism, ferrimagnetism and antiferromagnetism, contrary to the nonmagnetic properties of bulk alkali metals. The insulator-to-metal transition occurs depending on the loading density. These behaviors are overviewed in terms of the localized nature of superatoms, the electron transfer between them and the polaron effect by the interaction between s-electrons and cation displacements. The competitions among them provide us an exotic electron system of the solid state physics.