Correlated Terahertz phonon-ion interactions control ion conduction in a solid electrolyte
Abstract
Ionic conduction in solids that exceeds 1 mS/cm is predicted to involve coupled phonon-ion interactions in the crystal lattice. Here, we use theory and experiment to measure the possible contribution of coupled phonon-ion hopping modes which enhance Li+ migration in Li0.5La0.5TiO3 (LLTO). The ab initio calculations predict that the targeted excitation of individual TiO6 rocking modes greatly increases the Li+ jump rate as compared to the excitation of vibrational modes associated with heating. Experimentally, coherently driving TiO6 rocking modes via terahertz (THz) illumination leads to a ten-fold decrease in the differential impedance compared to the excitation of acoustic and optical phonons. Additionally, we differentiate the ultrafast responses of LLTO due to ultrafast heating and THz-range vibrations using laser-driven spectroscopy (LUIS), finding a unique long-lived response for the THz-range excitation. These findings provide new insights into coupled ion migration mechanisms, indicating the important role of THz-range coupled phonon-ion hopping modes in enabling fast ion conduction at room temperature.
Cite
@article{arxiv.2305.01632,
title = {Correlated Terahertz phonon-ion interactions control ion conduction in a solid electrolyte},
author = {Kim H. Pham and Kiarash Gordiz and Natan A. Spear and Amy K. Lin and Jonathan M. Michelsen and Hanzhe Liu and Daniele Vivona and Geoffrey A. Blake and Yang Shao-Horn and Asegun Henry and Kimberly A. See and Scott K. Cushing},
journal= {arXiv preprint arXiv:2305.01632},
year = {2025}
}
Comments
13 pages, 6 figures