Mott insulating state in incommensurate molecular conductors

非整合分子性導体におけるモット絶縁体状態

妹尾 仁嗣; 吉岡 英生*; 大塚 雄一*

Seo, Hitoshi; Yoshioka, Hideo*; Otsuka, Yuichi*

分子性導体のうち二つの分子種の組成比が互いに非整合なもの、すなわち非整合分子性導体において、モット絶縁体状態の可能性を理論的に調べた。これらの物質ではバンド充填率が無理数となり金属状態が期待されるにもかかわらず、価電子間のオンサイトクーロン斥力とキャリアを供給する閉殻イオンからのポテンシャルによって、元にある格子とは周期が非整合にキャリアが局在する「非整合モット絶縁体」が実現しうることを示す。

We theoretically investigate the possibility of a Mott insulating state in a class of molecular conductors where the composition ratio between two molecular species is incommensurate to each other, i.e., incommensurate molecular conductors. Although the band-filling becomes irrational and then metallic behavior would be expected, the on-site Coulomb repulsion among the valence electrons together with the potential from the closed-shellions supplying the carriers can give rise to an "incommensurate Mott insulator", which is characterized by the carriers being localized with a period incommensurate to the underlying lattice.