Publication: Suppression of localization in Kronig-Penney models with correlated disorder
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1994-01-01
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American Physical Society
Abstract
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 briefly discuss the
relevance of these results in several physical contexts.
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Physical Review B, vol. 49, n. 1, 1 jan. 1994. Pp. 147-157