Delocalized 2-magnons eigenstates in long-range correlated random Heisenberg chains

Dias, W. S.; Nascimento, E. M.; Moura, F. A. B. F. de; Lyra, M. L.

doi:10.1016/j.jmmm.2009.02.120

Cited by 5 publications

(2 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The elastic constants η i will be considered as a long-range correlated random sequence. In order to generate sequences with a power-law decaying spectral density function, we firstly generate the following auxiliary sequence [5,29]:…”

Section: Model and Formalismmentioning

confidence: 99%

Absence of localized acoustic waves in a scale-free correlated random system

Costa

Moura²

2011

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We numerically study the propagation of acoustic waves in a one-dimensional medium with a scale-free long-range correlated elasticity distribution. The random elasticity distribution is assumed to have a power spectrum S(k) ∼ 1/k α . By using a transfer-matrix method we solve the discrete version of the scalar wave equation and compute the localization length. In addition, we apply a second-order finite-difference method for both the time and spatial variables and study the nature of the waves that propagate in the chain. Our numerical data indicate the presence of extended acoustic waves for a high degree of correlations. In contrast with local correlations, we numerically demonstrate that scale-free correlations promote a stable phase of free acoustic waves in the thermodynamic limit.

show abstract

Section: Model and Formalismmentioning

confidence: 99%

Absence of localized acoustic waves in a scale-free correlated random system

Costa

Moura²

2011

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…The formalism of the localization theory applies also to the study of magnon localization in random ferromagnets [18,19], collective vibrational motion of one-dimensional (1D) disordered harmonic chains [20][21][22] and acoustic waves in disordered media [23][24][25][26][27][28][29][30][31][32][33][34][35]. In fact, the propagation of acoustic waves has attracted both theoretical [23][24][25][26][27][28][29][30][31][33][34][35] and experimental [32] interest.…”

Section: Introductionmentioning

confidence: 99%

Extended acoustic modes in random systems withn-mer short range correlations

Barros

Costa

Moura

2011

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

In this paper we study the propagation of acoustic waves in a one-dimensional medium with a short range correlated elasticity distribution. In order to generate local correlations we consider a disordered binary distribution in which the effective elastic constants can take on only two values, η(A) and η(B). We add an additional constraint that the η(A) values appear only in finite segments of length n. This is a generalization of the well-known random-dimer model. By using an analytical procedure we demonstrate that the system displays n - 1 resonances with frequencies ω(r). Furthermore, we apply a numerical transfer matrix formalism and a second-order finite-difference method to study in detail the waves that propagate in the chain. Our results indicate that all the modes with ω ≠ ω(r) decay and the medium transmits only the frequencies ω(r).

show abstract