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Delocalized 2-magnons eigenstates in long-range correlated random Heisenberg chains
- Source :
-
Journal of Magnetism & Magnetic Materials . Aug2009, Vol. 321 Issue 15, p2304-2310. 7p. - Publication Year :
- 2009
-
Abstract
- Abstract: We consider the one-dimensional quantum disordered Heisenberg ferromagnetic chain model with long-range correlated exchange couplings and study the nature of collective two-spin excitations. By using an exact diagonalization of the Hamiltonian in the two-spin flip subspace, we compute the spin wave participation number to characterize the localized or delocalized nature of the two-magnon states. For strongly correlated random exchange couplings, extended two-spin excitations with finite energy appear. Integrating the time-dependent Schroedinger equation, we follow the time-evolution of an initially localized two-spin state. We find that, associated with the emergence of extended spin waves, the wave-packet mean-square displacement develops a ballistic spread. Further, the single-spin wave-packet acquires an asymmetric profile due to the kinematic interaction between the excited spins. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 03048853
- Volume :
- 321
- Issue :
- 15
- Database :
- Academic Search Index
- Journal :
- Journal of Magnetism & Magnetic Materials
- Publication Type :
- Academic Journal
- Accession number :
- 39893914
- Full Text :
- https://doi.org/10.1016/j.jmmm.2009.02.120