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arXiv 0901.0284cond-mat.dis-nn
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Anderson金属-绝缘体转变时典型波函数多重分形谱的终止:用泛函重整化群的场论描述

Termination of typical wavefunction multifractal spectra at the Anderson metal-insulator transition: Field theory description using the functional renormalization group

Matthew S. Foster, Shinsei Ryu, Andreas W. W. Ludwig

摘要:

我们重新讨论了d > 2空间维度中无相互作用电子的Anderson金属-绝缘体跃迁(MIT)的波函数统计问题。在过渡,复杂的空间结构的临界波函数反映在多重分形谱的广义逆参与比(IPRs)的非线性行为。除了从窄到宽IPR统计的交叉之外,这总是发生在波函数振幅的足够大的时刻,从与特定无序实现相关的典型波函数获得的谱与从无序平均IPR获得的谱明显不同。这种现象被称为多重分形谱的终止。我们提供了一个典型的多重分形谱的终止场论推导,通过结合非线性西格玛模型框架,传统上用于访问MIT在d = 2 + 10维,与功能重整化群(FRG)技术。本文采用的FRG方法最初是为了研究二维(2D)随机相位XY模型的性质[D. Carpentier和P. Le Doussal,Nucl.Phys.B588,565(2000)]。同样的方法被用来证明终止的多重分形谱在非常特殊的问题,二维狄拉克费米子服从随机阿贝尔矢量势。结果表明,在非线性西格玛模型的标准场论框架下,当与FRG相结合时,可以在d > 2的一般安德森局域化跃迁处得到典型的多重分形波函数谱及其终止.

英文摘要:

We revisit the problem of wavefunction statistics at the Anderson metal-insulator transition (MIT) of non-interacting electrons in d > 2 spatial dimensions. At the transition, the complex spatial structure of the critical wavefunctions is reflected in the non-linear behavior of the multifractal spectrum of generalized inverse participation ratios (IPRs). Beyond the crossover from narrow to broad IPR statistics, which always occurs for sufficiently large moments of the wavefunction amplitude, the spectrum obtained from a typical wavefunction associated with a particular disorder realization differs markedly from that obtained from the disorder-averaged IPRs. This phenomenon is known as the termination of the multifractal spectrum. We provide a field theoretical derivation for the termination of the typical multifractal spectrum, by combining the non-linear sigma model framework, conventionally used to access the MIT in d = 2 + epsilon dimensions, with a functional renormalization group (FRG) technique. The FRG method deployed here was originally pioneered to study the properties of the two-dimensional (2D) random phase XY model [D. Carpentier and P. Le Doussal, Nucl. Phys. B 588, 565 (2000)]. The same method was used to demonstrate the termination of the multifractal spectrum in the very special problem of 2D Dirac fermions subject to a random Abelian vector potential. Our result shows that the typical multifractal wavefunction spectrum and its termination can be obtained at a generic Anderson localization transition in d > 2, within the standard field theoretical framework of the non-linear sigma model, when combined with the FRG.

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