Researchers from the University of Potsdam, including Sven Lohmann, Quinn Emilia Fischer, Justus Leiber, and Philipp Maass, have recently published a study in the Journal of Chemical Physics that sheds light on the behavior of conductivity in disordered solids, a topic of significant interest to the energy sector, particularly in the development of advanced battery and semiconductor technologies.
The study focuses on a phenomenon known as universal time-temperature scaling of conductivity spectra, which has been previously explained by a model involving thermally activated hopping of noninteracting particles over random energy barriers. However, a key question remained: does this model, known as the random barrier model, accurately account for the disorder in site energies observed in real materials?
To address this question, the researchers employed a novel approach, mapping the behavior of many particles hopping in a disordered site energy landscape to that of independent particles in a barrier landscape. Their findings reveal that, in the low temperature limit, the associated barrier model correctly describes the time-temperature scaling behavior. However, at higher temperatures, the site energy model demonstrates better scaling behavior, aligning with experimental observations.
The researchers also extended their mapping to different types of mobile charge carriers. This broader perspective allowed them to understand why time-temperature superposition, a phenomenon where the effects of time and temperature on a material’s properties can be separated, can be absent in mixed alkali glasses.
This research provides valuable insights into the behavior of conductivity in disordered solids, which is crucial for the development of advanced energy storage and semiconductor technologies. By better understanding and predicting the behavior of these materials, the energy industry can potentially improve the performance and efficiency of batteries, solar cells, and other electronic devices.
This article is based on research available at arXiv.