Controlled engineering of extended states in disordered systems
Controlled engineering of extended states in disordered systems
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DOI：
10.1103/physrevb.86.085119
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发表时间：
2012-06
影响因子：
3.7
通讯作者：
Alberto Rodríguez;A. Chakrabarti;R. A. Romer
中科院分区：
文献类型：
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作者：
Alberto Rodríguez;A. Chakrabarti;R. A. Romer
我们描述了如何在d - bbbb1维的紧密结合哈密顿模型的无序系统中设计波函数离域。我们分析地表明，随机现场势能的简单积结构，加上适当选择的跳变强度，允许共振散射过程导致沿一个方向的弹道输运，以及光谱中扩展布洛赫态和各向异性局域态的可控共存。我们证明了这些特征在系统参数连续范围内的热力学极限中持续存在。数值结果支持这些发现，并突出了相对于有限系统的精确共振条件的偏差，扩展制度的鲁棒性。系统的定位和输运特性几乎可以随意设计，并且在每个方向上都是独立的。这项研究为设计作为量子波（如光晶格中的物质波）的开关器件和带通滤波器的无序电位提供了可能性。
We describe how to engineer wave-function delocalization in disordered systems modeled by tight-binding Hamiltonians in d>1 dimensions. We show analytically that a simple product structure for the random on-site potential energies, together with suitably chosen hopping strengths, allows a resonant scattering process leading to ballistic transport along one direction, and a controlled coexistence of extended Bloch states and anisotropically localized states in the spectrum. We demonstrate that these features persist in the thermodynamic limit for a continuous range of the system parameters. Numerical results support these findings and highlight the robustness of the extended regime with respect to deviations from the exact resonance condition for finite systems. The localization and transport properties of the system can be engineered almost at will and independently in each direction. This study gives rise to the possibility of designing disordered potentials that work as switching devices and band-pass filters for quantum waves, such as matter waves in optical lattices.