On the electron-energy loss spectra and plasmon resonance in cuprates

TL;DR

This paper investigates how the layered structure and non-Drude charge response in cuprates influence electron-energy loss spectra, revealing nearly critically damped plasmon resonances and low-energy loss features consistent with experimental observations.

Contribution

It provides a theoretical analysis of plasmon damping and loss functions in cuprates, incorporating the layered structure and t-J model, aligning with experimental data.

Findings

Plasmon resonance is nearly critically damped in intermediate doping.

Anomalous frequency dependence affects the low-energy loss function.

Theoretical results agree with measured plasmon frequencies.

Abstract

The consequences of the non-Drude charge response in the normal state of cuprates and the effect of the layered structure on electron-energy loss spectra are investigated, both for experiments in the transmission and the reflection mode. It is shown that in the intermediate doping regime the plasmon resonance has to be nearly critically damped as a result of the anomalous frequency dependence of the relaxation rate. This also implies an unusual low-energy dependence of the loss function. Both facts are consistent with experiments in cuprates. Our study based on the t-J model shows good agreement with measured plasmon frequencies.