Europhys. Lett.
Volume 68, Number 5, December 2004
Page(s) 678 - 684
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 05 November 2004
Europhys. Lett., 68 (5), pp. 678-684 (2004)
DOI: 10.1209/epl/i2004-10267-5

The Anderson metal-insulator transition in the presence of scale-free disorder

M. L. Ndawana1, R. A. Römer1 and M. Schreiber2

1  Department of Physics and Centre for Scientific Computing, University of Warwick Coventry, CV4 7AL, UK
2  Institut für Physik, Technische Universität Chemnitz - 09107 Chemnitz, Germany

received 27 April 2004; accepted in final form 8 October 2004
published online 5 November 2004

We investigate the three-dimensional Anderson model of localization via a modified transfer matrix method in the presence of scale-free diagonal disorder characterized by a disorder correlation function g(r) decaying asymptotically as $r^{-\alpha}$. We study the dependence of the localization length exponent $\nu$ on the correlation strength exponent $\alpha$. For fixed disorder W, there is a critical $\alpha_{\ab{c}}$, such that for $\alpha<\alpha_{\ab{c}}$, $\nu=2/\alpha$ and for $\alpha
>\alpha_{\ab{c}}$ , $\nu$ remains that of the uncorrelated system in accordance with the extended Harris criterion. At the band center, $\nu$ is independent of $\alpha$ but equal to that of the uncorrelated system. The physical mechanisms leading to this different behavior are discussed.

71.30.+h - Metal-insulator transitions and other electronic transitions.
72.10.Bg - General formulation of transport theory.
72.15.Rn - Localization effects (Anderson or weak localization).

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