Characterization of temperature-induced randomness in the dynamics of vibration

The nature of the dynamics of vibrations in an amorphous material provides the chance for other modeling approaches such as random matrix theory. This method provides an alternate approach to model materials' evolution in time. So far, the random matrix method applies to amorphous materials due to the random nature of vibrations that stems from the random structure of amorphous materials. This work evaluates the possibility of finding random behavior in crystalline materials at different temperatures and different potential conditions. In our approach, we hypothesis temperature being the source of randomness, and we evaluate the hypothesis by comparing two cases of vibrations in the same material. One of the cases is the time evolution of Aragon under the Lennard Jones potential, and the other case is the same system with added randomness to its dynamics through Brownian dynamics. To support our result, we also utilize the terminology and methods developed to analyze the dynamics of vibrations in amorphous materials to evaluate and characterize the vibrations in the same Argon system at different temperatures and having modified strength of the potential. Our results show changes in the lifetime of the modes with the addition of randomness to the system. The difference between the lifetime of the modes in an Argon system with and without randomness vanished with increasing temperature. This observation is also supported by observing local non-coherent modes with the increase of the temperature, and we found less localization in an argon system having stronger potential. As a result, we concluded that using a method that tunes the randomness can model crystalline materials at high temperatures.