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Delocalization and Spin-wave Dynamics in Ferromagnetic Chains with Long-range Correlated Random Exchange by de Moura, F. A. B. F.; Coutinho-Filho, M. D.; Raposo, E. P.; Lyra, M. L. is a scholarly article available to read on EtoBox.

What is Delocalization and Spin-wave Dynamics in Ferromagnetic Chains with Long-range Correlated Random Exchange about?

We study the one-dimensional quantum Heisenberg ferromagnet with exchange couplings exhibiting long-range correlated disorder with power spectrum proportional to $1/k^{\alpha}$, where $k$ is the wave-vector of the modulations on the random coupling landscape. By using renormalization group, integration of the equations of motion and exact diagonalization, we compute the spin-wave localization length and the mean-square displacement of the wave-packet. We find that, associated with the emergence of extended spin-waves in the low-energy region for $\alpha > 1$, the wave-packet mean-square displacement changes from a long-time super-diffusive behavior for $\alpha <1$ to a long-time ballistic behavior for $\alpha > 1$. At the vicinity of $\alpha =1$, the mobility edge separating the extended and localized phases is shown to scale with the degree of correlation as $E_c\propto (\alpha -1)^{1/3}$.

Author

de Moura, F. A. B. F.; Coutinho-Filho, M. D.; Raposo, E. P.; Lyra, M. L.

Published

2002

Language

EN