title: Enhanced localization, energy anomalous diffusion and resonant mode in harmonic chains with correlated mass-spring disorder.
abstract: In this work, we study the vibrational modes and energy spreading in a harmonic chain model with diluted second-neighbors couplings and correlated mass-spring disorder. While all nearest neighbor masses are coupled by an elastic spring, second neighbors springs are introduced with a probability pD. The masses are randomly distributed according to the site connectivity mi = m0 (1 + 1/n(α)(I), where ni is the connectivity of the site i and α is a tunable exponent. We show that maximum localization of the vibrational modes is achieved for α ≃ 3/4. The time-evolution of the energy wave-packet is followed after an initial localized excitation. While the participation number remains finite, the energy spread is shown to be sub-diffusive after a displacement and super-diffusive after an impulse excitation. These features are related to the development of a power-law tail in the wave-packet distribution. Further, we unveil that the spring dilution leads to the emergence of a resonant localized state which is signaled by a van Hove singularity in the density of states.
authors.affiliation: Curso de Física, Universidade Federal de Alagoas, Campus Arapiraca, Arapiraca-AL, 57309-005, Brazil.
authors.forename: S S
authors.initials: SS
authors.lastname: de Albuquerque
authors.forename: J L L
authors.initials: JL
authors.lastname: dos Santos
authors.forename: F A B F
authors.initials: FA
authors.lastname: de Moura
authors.forename: M L
authors.initials: ML
authors.lastname: Lyra