Magnon delocalization in ferromagnetic chains with long-range correlated disorder

Abstract

We study one-magnon excitations in a random ferromagnetic Heisenberg chain with long-range correlations in the coupling constant distribution. By employing an exact diagonalization procedure, we compute the localization length of all one-magnon states within the band of allowed energies $E$. The random distribution of coupling constants was assumed to have a power spectrum decaying as $S(k)\propto 1/k^{\alpha }$. We found that for $\alpha <1$, one-magnon excitations remain exponentially localized with the localization length $\xi$ diverging as 1/E. For $\alpha =1$ a faster divergence of $\xi$ is obtained. For any $\alpha >1$, a phase of delocalized magnons emerges at the bottom of the band. We characterize the scaling behavior of the localization length on all regimes and relate it with the scaling properties of the long-range correlated exchange coupling distribution.

7 Pages, 5 figures, to appear in Phys. Rev. B

Cited by in corpus (10)

• Delocalization in harmonic chains with long-range correlated random masses
• Violation of the fluctuation-dissipation theorem for fast superdiffusion
• Delocalization and spin-wave dynamics in ferromagnetic chains with long-range correlated random exchange
• Disorder-assisted distribution of entanglement in $XY$ spin chains
• High-fidelity state transfer through long-range correlated disordered quantum channels
• Wannier-Stark ladder in the linear absorption of a random system with scale-free disorder
• Entanglement generation between distant parties via disordered spin chains
• Magnon-polaron formation in XXZ quantum Heisenberg chains
• Scaling behavior of a one-dimensional correlated disordered electronic System
• Bound states in one-dimensional systems with colored noise