Long-range correlations in disordered graphene
Long-range correlations in disordered graphene
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DOI：
10.1103/physrevb.78.125401
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发表时间：
2008-06
影响因子：
3.7
通讯作者：
K. Ziegler
中科院分区：
文献类型：
--
作者：
K. Ziegler
研究了具有随机矢势的类Dirac旋量模型在Dirac点附近的长程关联现象。这些关联源于自发破缺的对称性及其相应的Goldstone模。使用强无序扩展，相关函数和矩阵元素进行了分析，并与弱无序扩展的结果进行了比较。局域态密度关联和狄拉克点上下态的重叠具有长程行为的特征。关联范围随着离狄拉克点的距离而减小。输运是扩散的，对于任何无序强度，扩散系数与单粒子散射时间成正比。粒子-空穴散射的特殊性质的一个结果是弱无序和强无序的恒定微波电导率，描述了与传统的Drude输运的偏离。该模型的一些性质可以与一种由无序产生的近藤尺度联系起来。最后，在狄拉克点的波函数的性质的特点是他们的参与率，表明在狄拉克点的临界状态。
The appearence of long-range correlations near the Dirac point of a Dirac-like spinor model with random vector potential is studied. These correlations originate from a spontaneously broken symmetry and their corresponding Goldstone modes. Using a strong-disorder expansion, correlation functions and matrix elements are analyzed and compared with results from a weak-disorder expansion. The local density of states correlation and the overlap between states above and below the Dirac point are characterized by a long-range behavior. The correlation range decreases with the distance from the Dirac point. Transport is diffusive and the diffusion coefficient is proportional to the one-particle scattering time for any strength of disorder. A consequence of the special properties of particle-hole scattering is a constant microwave conductivity for weak as well as for strong disorder, describing a deviation from conventional Drude-like transport. Some properties of the model can be linked to a kind of Kondo scale, which is generated by disorder. Finally, the properties of the wave functions at the Dirac point are characterized by their participation ratios, indicating a critical state at the Dirac point.