Europhys. Lett.
Volume 66, Number 4, May 2004
Page(s) 585 - 591
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 May 2004
Europhys. Lett., 66 (4) , pp. 585-591 (2004)
DOI: 10.1209/epl/i2003-10238-4

Delocalization and ballistic dynamics in the two-dimensional Anderson model with long-range correlated disorder

F. A. B. F. de Moura1, 2, M. D. Coutinho-Filho1, M. L. Lyra2 and E. P. Raposo1

1  Laboratório de Física Teórica e Computacional, Departamento de Física Universidade Federal de Pernambuco - 50670-901 Recife, PE, Brazil
2  Departamento de Física, Universidade Federal de Alagoas Maceió AL 57072-970, Brazil

(Received 18 November 2003; accepted in final form 17 March 2004)

We study the nature of one-electron eigenstates in a two-dimensional ( 2d) Anderson model with long-range correlated disorder. Long-range correlations are introduced by using a 2d discrete Fourier method which generates an appropriated disorder distribution with spectral density $S(k)\propto
1/k^{\alpha_{2d}}$ . Our numerical data suggest that the exponents governing the collapse of the participation function for low energies ( $\xi\propto N^{D_2}$) and the long time decay of the autocorrelation function ( $C(t) \propto t^{-\beta}$) satisfy the scaling relation $D_2=\beta d$. They also imply that the system exhibits a crossover from a diffusive spread for weakly correlated disorder to a ballistic dynamics associated with the emergence of extended states in the strongly correlated disorder regime $(\alpha_{2d}>2)$.

78.30.Ly - Disordered solids.
71.30.+h - Metal-insulator transitions and other electronic transitions.
73.20.Jc - Delocalization processes.

© EDP Sciences 2004