Nakatsuji S, Dobrosavljević V, Tanasković D, Minakata M, Fukazawa H, Maeno Y
Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Phys Rev Lett. 2004 Oct 1;93(14):146401. doi: 10.1103/PhysRevLett.93.146401. Epub 2004 Sep 27.
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.
通过结合详细的实验研究和简单的理论论证，我们确定了一种新颖的机制，该机制表征了接近金属 - 绝缘体转变的Ca2-xSrxRuO4的莫特绝缘相中的跳跃输运。跳跃指数α呈现出系统的演变，从绝缘体深处的α = 1/2值到更接近转变的传统莫特值α = 1/3。我们认为这种行为是接近金属 - 绝缘体转变的无序莫特系统的普遍特征，它反映了填充莫特 - 哈伯德能隙的无序诱导局域电子态的逐渐出现。
