Europhys. Lett.
Volume 65, Number 1, January 2004
Page(s) 75 - 81
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 December 2003
Europhys. Lett., 65 (1) , pp. 75-81 (2004)
DOI: 10.1209/epl/i2003-10056-8

Anti-localisation to strong localisation: The interplay of magnetic scattering and structural disorder

S. Kumar and P. Majumdar

Harish-Chandra Research Institute - Chhatnag Road, Jhusi, Allahabad 211 019, India

(Received 14 July 2003; accepted 26 October 2003)

We study the effect of magnetic scattering on transport in a system with strong structural disorder, using exact finite-size calculation of the low-frequency optical conductivity. At weak electron-spin coupling, spin disorder leads to a decrease in resistivity, by weakening the quantum interference precursors to Anderson localisation. However, at strong electron-spin coupling, the "double exchange" limit, magnetic scattering increases the effective disorder, sharply increasing the resistivity. We illustrate the several unusual transport regimes in this strong-disorder problem, identify a re-entrant insulator-metal-insulator transition, and map out the phase diagram at a generic electron density.

72.10.Bg - General formulation of transport theory.
72.15.Qm - Scattering mechanisms and Kondo effect.
72.15.Rn - Localization effects (Anderson or weak localization).

© EDP Sciences 2004