title: Metallic state in a lime-alumina compound with nanoporous structure.
abstract: We report a metallic state in a nanostructured porous crystal 12CaO x 7Al2O3 by incorporating electrons in the inherent subnanometer-sized cages, in which a three-dimensionally closely packed cage structure acts as an electronic conduction path. High-density electron doping ( approximately 2 x 10(21) cm(-3)), which was achieved by a thermal treatment in Ti metal vapor at approximately 1100 degrees C, induces homogenization of the cage geometry to a symmetric state, resulting in an insulator-metal transition with a sharp enhancement of the electron drift mobility from approximately 0.1 to 4 cm(2) V(-1) s(-1). The results provide an approach for the realization of electroactive functions in materials composed only of environmentally benign elements by utilizing the appropriate nanostructures.
authors: Frontier Collaborative Research Center, Tokyo Institute of Technology, Mail Box S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Sung Wng
authors: SW
authors: Kim
authors: Satoru
authors: S
authors: Matsuishi
authors: Takatoshi
authors: T
authors: Nomura
authors: Yoshiki
authors: Y
authors: Kubota
authors: Masaki
authors: M
authors: Takata
authors: Katsuro
authors: K
authors: Hayashi
authors: Toshio
authors: T
authors: Kamiya
authors: Masahiro
authors: M
authors: Hirano
authors: Hideo
authors: H
authors: Hosono