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Metallic State in a Lime−Alumina Compound with Nanoporous Structure

2007; American Chemical Society; Volume: 7; Issue: 5 Linguagem: Inglês

10.1021/nl062717b

1530-6992

Sung Wng Kim, Satoru Matsuishi, Takatoshi Nomura, Yoshiki Kubota, Masaki Takata, Katsuro Hayashi, Toshio Kamiya, Masahiro Hirano, Hideo Hosono,

Advanced Condensed Matter Physics

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.