Displaced Drude peak and bad metal from the interaction with slow fluctuations

Scattering by slowly fluctuating degrees of freedom can cause a transient localization of the current-carrying electrons in metals, driving the system away from normal metallic behavior. We illustrate and characterize this general phenomenon by studying how signatures of localization emerge in the optical conductivity of electrons interacting with slow bosonic fluctuations. The buildup of quantum localization corrections manifests itself in the emergence of a displaced Drude peak (DDP), whose existence strongly alters the low frequency optical response and suppresses the d.c. conductivity. We find that for sufficiently strong interactions, many-body renormalization of the fluctuating field induced at metallic densities enhances electron localization and the ensuing DDP phenomenon in comparison with the well-studied low concentration limit. Our results are compatible with the frequent observation of DDPs in electronic systems where slowly fluctuating degrees of freedom couple significantly to the charge carriers.

Automated summary

This study illustrates and characterizes the phenomenon of transient localization of current-carrying electrons in metals caused by scattering from slowly fluctuating degrees of freedom, leading the system away from normal metallic behavior. Strong interactions at metallic densities enhance electron localization and the emergence of a displaced Drude peak (DDP), altering low frequency optical response and suppressing d.c. conductivity. This phenomenon is commonly observed in electronic systems where slowly fluctuating degrees of freedom significantly couple to charge carriers.