LOCALIZATION AND DEPHASING EFFECTS IN A TIME-DEPENDENT ANDERSON HAMILTONIAN
LOCALIZATION AND DEPHASING EFFECTS IN A TIME-DEPENDENT ANDERSON HAMILTONIAN
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DOI：
10.1021/j100366a027
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发表时间：
1990-02-08
影响因子：
--
通讯作者：
WOLYNES, PG
中科院分区：
文献类型：
--
作者：
EVENSKY, DA;SCALETTAR, RT;WOLYNES, PG
1. Introduction The peculiarities of charge and exciton transport in solids have intrigued scientists for many decades. Even in the 1920s, students of chemical physics were aware of the perplexing nature of these problems and proposed experimental and theoretical approaches. 1 In fact, these are highly quantum mechanical phenomena relying on the precise tuning of energy levels. That essential physical insight was provided by Peierls1 2 and Wilson3for perfect crystals and by Anderson4for disordered systems. The seminal experimental work using this insight was done by Drickamer5 who showed that pressure tuning could effect a metal-insulator transition in crystalline materials. Pressure (stress) tuning features prominently in the experimental work on electron transport in disordered materials as well. 6 It has also been used by Drickamer in his pioneering study of excitontransport. 7 Since conduction and electron transport rely on tuning of energy levels, it is obviously of interest to examine theinfluence of dynamic fluctuations in energy levels on these processes. In this contribution we report simulations addressing that issue in the context of disordered systems. The Anderson model of localization is one of the simplest descriptions of the physics of disordered systems. It describes the transition, with increasing disorder, from the usual extended Bloch states charcteristic of periodic crystalline potentials to states which are spatially localized. The Anderson model has been extensively studied by a variety of analytical and numerical techniques. 8 It is now widely believed that any amount of disorder in one and two dimensions results in localization of the eigenfunctions. In three dimensions, there is a critical amount of disorder required for the delocalizedstates to disappear. Near the edge of the band, where the density of states is least, localization appears first. A Mott mobility edge separates these states from extended ones closer to the band center.
