Signature of stripe pinning in optical conductivity

TL;DR

This paper investigates how charge stripes in cuprates respond to electric fields, revealing impurity pinning effects that explain observed infrared peaks in optical conductivity measurements.

Contribution

It introduces a diagrammatic approach to analyze stripe pinning effects on optical conductivity, providing a unified explanation for experimental infrared peaks.

Findings

Stripe modes shift to finite frequency due to impurity pinning.

Calculated energy scales match experimental infrared peaks.

Analysis applies to both single and interacting stripe arrays.

Abstract

The response of charge stripes to an external electric field applied perpendicular to the stripe direction is studied within a diagrammatic approach for both weak and strong pinning by random impurities. The sound-like mode of the stripes described as elastic strings moves to finite frequency due to impurity pinning. By calculating the optical conductivity we determine this characteristic energy scale for both a single stripe and an array of interacting stripes. The results explain the anomalous far-infrared peak observed recently in optical-conductivity measurements on cuprates.