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arXiv 0708.3585cond-mat.mes-hall
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手征二维随机流模型的临界电导

Critical conductance of the chiral 2d random flux model

L. Schweitzer, P. Markoš

摘要:

本文用传输矩阵方法研究了正方形格子上随机磁通模型在带中心的两端电导。由于手征对称性,存在一个临界点,在该临界点处系综平均电导与尺度无关。我们还研究了电导分布函数,它取决于边界条件和晶格位置的数量是偶数或奇数。我们推导出一个临界指数$ν=0.42\pm 0.05$的正方形样品的宽度均匀使用一个参数缩放的电导。由于明显的有限尺寸效应,这一结果以前不能从准一维系统中的局部化长度的发散中获得。

英文摘要:

The two-terminal conductance of a random flux model defined on a square lattice is investigated numerically at the band center using a transfer matrix method. Due to the chiral symmetry, there exists a critical point where the ensemble averaged mean conductance is scale independent. We also study the conductance distribution function which depends on the boundary conditions and on the number of lattice sites being even or odd. We derive a critical exponent $ν=0.42\pm 0.05$ for square samples of even width using one-parameter scaling of the conductance. This result could not be obtained previously from the divergence of the localization length in quasi-one-dimensional systems due to pronounced finite-size effects.

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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