Carpena Pedro, Bernaola-Galván Pedro, Ivanov Plamen Ch, Stanley H Eugene
Departamento de Física Aplicada II, ETSI de Telecomunicación, Universidad de Málaga, 29071 Málaga, Spain.
Nature. 2002 Aug 29;418(6901):955-9. doi: 10.1038/nature00948.
According to Bloch's theorem, electronic wavefunctions in perfectly ordered crystals are extended, which implies that the probability of finding an electron is the same over the entire crystal. Such extended states can lead to metallic behaviour. But when disorder is introduced in the crystal, electron states can become localized, and the system can undergo a metal-insulator transition (also known as an Anderson transition). Here we theoretically investigate the effect on the physical properties of the electron wavefunctions of introducing long-range correlations in the disorder in one-dimensional binary solids, and find a correlation-induced metal-insulator transition. We perform numerical simulations using a one-dimensional tight-binding model, and find a threshold value for the exponent characterizing the long-range correlations of the system. Above this threshold, and in the thermodynamic limit, the system behaves as a conductor within a broad energy band; below threshold, the system behaves as an insulator. We discuss the possible relevance of this result for electronic transport in DNA, which displays long-range correlations and has recently been reported to be a one-dimensional disordered conductor.
根据布洛赫定理，在完全有序的晶体中电子波函数是扩展的，这意味着在整个晶体中找到一个电子的概率是相同的。这种扩展态可导致金属行为。但是当晶体中引入无序时，电子态会局域化，并且系统会经历金属-绝缘体转变（也称为安德森转变）。在此，我们从理论上研究在一维二元固体的无序中引入长程关联对电子波函数物理性质的影响，并发现了一种关联诱导的金属-绝缘体转变。我们使用一维紧束缚模型进行数值模拟，并找到了表征系统长程关联的指数的阈值。高于此阈值且在热力学极限下，系统在一个宽能带内表现为导体；低于阈值时，系统表现为绝缘体。我们讨论了这一结果与DNA中电子输运可能的相关性，DNA显示出长程关联，并且最近被报道为一种一维无序导体。
