Mechanism of hopping transport in disordered mott insulators.
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.
Nakatsuji
S
S
Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Dobrosavljević
V
V
Tanasković
D
D
Minakata
M
M
Fukazawa
H
H
Maeno
Y
Y