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Electronic properties of alkali-metal loaded zeolites -- a "supercrystal" Mott insulator

Ryotaro Arita·Takashi Miyake·Takao Kotani·Mark van Schilfgaarde·Takashi Oka·Kazuhiko Kuroki·Yasuo Nozue·Hideo Aoki
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Abstract

First-principles band calculations are performed for the first time for an open-structured zeolite (LTA) with guest atoms (potassium) introduced in their cages. A surprisingly simple band structure emerges, which indicates that this system may be regarded as a "supercrystal", where each cluster of guest atoms with diameter $\sim$10Åacts as a "superatom" with well-defined $s$- and $p$-like orbitals, which in turn form the bands around the Fermi energy. The calculated Coulomb and exchange energies for these states turn out to be in the strongly-correlated regime. With the dynamical mean-field theory we show the system should be on the Mott-insulator side, and, on a magnetic phase diagram for degenerate-orbital systems, around the ferromagnetic regime, in accord with experimental results. We envisage this class of systems can provide a new avenue for materials design.

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Ryotaro Arita, Takashi Miyake, Takao Kotani, Mark van Schilfgaarde, Takashi Oka, Kazuhiko Kuroki, Yasuo Nozue, Hideo Aoki. 2003-06-11. Electronic properties of alkali-metal loaded zeolites -- a "supercrystal" Mott insulator. https://doi.org/10.1103/physrevb.69.195106

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