Thermoelectric ratchet effect for charge carriers with hopping dynamics
Résumé
We show that the huge Seebeck coeffcients observed recently for ionic conductors, arise from a
ratchet effect where activated jumps between neighbor sites are rectified by a temperature gradient,
thus driving mobile ions towards the cold. For complex systems with mobile molecules like
water or polyethylen glycol, there is an even more effcient diffusiophoretic transport mechanism,
proportional to the thermally induced concentration gradient of the molecular component. Without
free parameters, our model describes experiments on the ionic liquid EMIM-TFSI and hydrated
NaPSS, and it qualitatively accounts for polymer electrolyte membranes with Seebeck coeffcients
of hundreds of $k_B/e$.
Domaines
Matière Molle [cond-mat.soft]
Origine : Fichiers produits par l'(les) auteur(s)