Coherent magnon dynamics in ferromagnetic models with nonuniform magnetic field and correlated disorder

In this work we investigated the nature of the one-magnon eigenstates in a disordered chain at the presence of a non-uniform magnetic field. In our study, we analyzed the one-dimensional ferromagnetic Heisenberg model within the one-magnon framework. The spin-spin interaction was considered as a correlated disorder distribution with power law spectrum S(k)∝k−αS(k)∝k−α. By using numerical methods we calculated the time evolution of a initially localized Gaussian wave-packet. Our results reveal that for weak correlations (α<1)(α<1), the magnetic wave-packet remains localized around the initial position and for α>1α>1, we got an oscillatory profile similar to the Bloch-like phenomenology. We calculate the frequency of these oscillations and observed that it is in a good agreement with the semi-classical approach traditionally used to explain the Block-like oscillatory behavior.