title: Mechanism of hopping transport in disordered mott insulators.
abstract: By using a combination of detailed experimental studies and simple theoretical arguments, we identify a novel mechanism characterizing the hopping transport in the Mott insulating phase of Ca2-xSrxRuO4 near the metal-insulator transition. The hopping exponent alpha shows a systematic evolution from a value of alpha=1/2 deeper in the insulator to the conventional Mott value alpha=1/3 closer to the transition. This behavior, which we argue to be a universal feature of disordered Mott systems close to the metal-insulator transition, is shown to reflect the gradual emergence of disorder-induced localized electronic states populating the Mott-Hubbard gap.
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakatsuji
authors.forename: V
authors.initials: V
authors.lastname: Dobrosavljević
authors.forename: D
authors.initials: D
authors.lastname: Tanasković
authors.forename: M
authors.initials: M
authors.lastname: Minakata
authors.forename: H
authors.initials: H
authors.lastname: Fukazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Maeno