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arXiv 1306.6665cond-mat.dis-nncond-mat.mes-hall
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无序石墨烯中的电子局域化:波函数的多重分形性质

Electron localization in disordered graphene: multifractal properties of the wavefunctions

J. E. Barrios-Vargas, Gerardo G. Naumis

摘要:

通过数值多重分形分析,对掺杂石墨烯中的电子局域化特性进行了分析。通过得到紧束缚模型的奇异谱,发现电子波函数呈现多重分形行为。这种多重分形甚至对于第二近邻相互作用也是保留的,如果需要与实验结果进行比较,则需要考虑到这一点。随着杂质浓度的增加,靠近狄拉克点的态比远离狄拉克点的态具有更宽的多重分形特征。分析的结果可以得出结论,在分裂带的限制,杂质作为空缺,该系统可以很好地描述了一个手性正交对称类,与奇异谱过渡接近冻结无序增加。这也表明,在掺杂的石墨烯中,局域化与二维中的安德森局域化的传统图像相反,也表明二维系统中不存在量子逾渗的共同信念需要修正。

英文摘要:

An analysis of the electron localization properties in doped graphene is performed by doing a numerical multifractal analysis. By obtaining the singularity spectrum of a tight-binding model, it is found that the electron wave functions present a multifractal behavior. Such multifractality is preserved even for second neighbor interaction, which needs to be taken into account if a comparison is desired with experimental results. States close to the Dirac point have a wider multifractal character than those far from this point as the impurity concentration is increased. The analysis of the results allows to conclude that in the split-band limit, where impurities act as vacancies, the system can be well described by a chiral orthogonal symmetry class, with a singularity spectrum transition approaching freezing as disorder increases. This also suggests that in doped graphene, localization is in contrast with the conventional picture of Anderson localization in two dimensions, showing also that the common belief of the absence of quantum percolation in two dimensional systems needs to be revised.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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