Observation of the predicted charge collective mode of the Tc = 45 K superconducting phase of La2CuO4+{\delta}

TL;DR

This study reports the experimental detection of a predicted charge collective mode in La2CuO4+δ superconductors at 45 K, supporting a hierarchical two-component model of high-temperature superconductivity related to specific doping levels.

Contribution

First experimental observation of the predicted charge collective mode in La2CuO4+δ at the 45 K superconducting phase, validating the two-component charge texture model.

Findings

Detection of the Goldstone mode at ~72 cm-1 (~9 meV) in the superconducting phase.

Supports the hierarchical charge texture model at specific doping levels.

Correlates the mode with the superconducting transition temperature of 45 K.

Abstract

We report the far-infrared (far-IR) observation of the Goldstone mode at ~ 72 cm-1 (~ 9 meV) predicted to exist in the superconducting phase of the transition temperature (Tc) at 45 K in the La2CuO4-based superconductors. Our observation furthers the experimental support for the two-component picture where the localized charge texture, formed at a specific planar hole density (Ppl), is tied to the HTS at Tc = 15 K, 30 K, and 45 K in a hierarchical fashion at the so-called "magic" doping level at Ppl = 1/16, 2/16, and 3/16 respectively.