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Mechanism of hopping transport in disordered Mott insulators

S. Nakatsuji·V. Dobrosavljevic·D. Tanaskovic·M. Minakata·H. Fukazawa·Y. Maeno
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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 Ca$_{2-x}$Sr$_x$RuO$_4$ near the metal-insulator transition. The hopping exponent $α$ shows a systematic evolution from a value of $α=1/2$ deeper in the insulator to the conventional Mott value $α=1/3$ 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.

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S. Nakatsuji, V. Dobrosavljevic, D. Tanaskovic, M. Minakata, H. Fukazawa, Y. Maeno. 2004-08-11. Mechanism of hopping transport in disordered Mott insulators. https://doi.org/10.1103/physrevlett.93.146401

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