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

Abstract

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.

A stability bound on the $T$-linear resistivity of conventional metals

“…On the other hand, as has been emphasized in Ref. 19, weak localization may be an essential part of the physics (even at small λ and non-zero ω 0 ) when the resistivity is large enough, in particular in the high-temperature "bad metal" regime σ < ∼ e 2 /h.…”

Structural and Dynamic Disorder, Not Ionic Trapping, Controls Charge Transport in Highly Doped Conducting Polymers

“…The role of carriers’ interactions in a fluctuating energy landscape has been studied very recently, with results for different materials showing that many-body phenomena effectively contribute to the energetic disorder causing the transient localization of charge carriers. 12 One of the poorly understood questions concerns the role of Coulombic traps that the dopant ions may create in the density of states 13 and to which extent these are limiting transport at high carrier densities. Although the depth of these integer charge transfer complex (ICTC) states decreases as the potential wells between adjacent ions overlap, even at high doping levels the depth of these wells remains many times greater than the thermal energy at room temperature, kT ( Figure 1 a).…”

“…Coulomb forces concern both the interactions among carriers on polymer chains as well as between carriers and dopant ions. The role of carriers’ interactions in a fluctuating energy landscape has been studied very recently, with results for different materials showing that many-body phenomena effectively contribute to the energetic disorder causing the transient localization of charge carriers . One of the poorly understood questions concerns the role of Coulombic traps that the dopant ions may create in the density of states and to which extent these are limiting transport at high carrier densities.…”

A quantum theory of the nearly frozen charge glass

“…We now calculate how the incipient glassiness affects electron transport, making direct contact with available experiments. This is done in practice within the framework of transient localization theory [25][26][27]. The starting point consists in applying the Kubo-Greenwood formula to calculate the optical conductivity σ(ω) from the solution of the one-body electron problem in the electrostatic potential of the classical charges, which is obtained at each step of the MC evolution (see Sec.…”