Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 6: Postersitzung I (Amorphe- u. Tunnelsysteme, Niedrigdimensionale Systeme, Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter)

TT 6.23: Poster

Montag, 24. März 2003, 14:30–19:00, P2c, P2d

1D Anderson localization including next-nearest neighbour hopping — •Sebastian Papazoglou, Bernhard Kramer, and Stefan Kettemann — 1. Institut f. theor. Physik d. Univ. Hamburg

The canonical Anderson-model for spin-diffusion or transport in an amorphous semiconductor assumes hopping of the mobile entities between neighbouring sites. In our work the model is extended for the one -dimensional case including hopping to next-nearest neighbours. The localization length as a function of disorder-strength, energy and coupling-strength is calculated numerically by means of the transfer-matrix-method as well as the recursive-Green-function method [1]. It is found that above a certain relative coupling-strength to the next-nearest neighbour the localization length does not show its typical behaviour for one dimension which is due to the opening of a second transversal channel. It is also found that the known Wegner-anomaly in the band center shifts towards negative energies. Moreover, statistically independent coupled one-dimensional chains have been studied. In agreement with recent results by Zillmer et. al. [2] a singular behaviour of the localization length for vanishing coupling between the chains is found for the case of identical disorder strength in the chains.

[1] MacKinnon A, Kramer B, Rep. Prog. Phys. 53, (93) 1469 (1993).

[2] Zillmer R., Ahlers V., Pikovsky A., Europhys. Lett., 60, pp. 889-895 (2002).