Suppression of localization in kronig-penney models with correlated disorder



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Sáchez, A. and Maciá Barber, Enrique Alfonso and Domínguez-Adame Acosta, Francisco (1994) Suppression of localization in kronig-penney models with correlated disorder. Physical Review B, 49 (1). pp. 147-157. ISSN 0163-1829

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We consider the electron dynamics and transport properties of one-dimensional continuous models with random, short-range correlated impurities. We develop a generalized Poincare map formalism to cast the Schrodinger equation for any potential into a discrete set of equations, illustrating its application by means of a specific example. We then concentrate on the case of a Kronig-Penney model with dimer impurities. The previous technique allows us to show that this model presents infinitely many resonances (zeroes of the reflection coefficient at a single dimer) that give rise to a band of extended states, in contradiction with the general viewpoint that all one-dimensional models with random potentials support only localized states. We report on exact transfer-matrix numerical calculations of the transmission coefFicient, density of states, and localization length for various strengths of disorder. The most important conclusion so obtained is that this kind of system has a very large number of extended states. Multifractal analysis of very long systems clearly demonstrates the extended character of such states in the thermodynamic limit. In closing, we brieBy discuss the relevance of these results in several physical contexts.

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© 1994 The American Physical Society.
Thanks are warmly due to Rainer Scharf, who introduced us to the topic of the random dimer model and the suppresion of localization. All computations have been
carried out using facilities of the Universidad Carlos III de Madrid. A.S. acknowledges partial support from CICyT (Spain) through Project No. PB92-0248.

Uncontrolled Keywords:Random-Dimer Model, Conducting Polymers, Lattices, Transport, Absence; Systems, Media
Subjects:Sciences > Physics > Materials
ID Code:27825
Deposited On:19 Dec 2014 10:08
Last Modified:19 Dec 2014 10:08

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