Micro-Raman evidence for topological charge order across the superconducting dome of La_{2-x)SrxCuO4

TL;DR

This study uses micro-Raman spectroscopy to reveal how charge order and lattice dynamics evolve across the superconducting phase diagram of La_{2-x}Sr_xCuO_4, indicating a link between charge order and superconductivity.

Contribution

It provides new evidence of topological charge order in La_{2-x}Sr_xCuO_4 across the superconducting dome using micro-Raman spectroscopy.

Findings

Charge ordering signatures are observed well above T_c.

Phonon modes show doping-dependent behavior linked to structural transitions.

Charge order correlates with superconducting transition temperature.

Abstract

The doping dependence of the micro-Raman spectra of high quality La_{2-x}Sr_xCuO_4 microcrystals with x=0.0-0.45 has been investigated in the region 10-300 K. The phonon at ~100 cm^{-1} of the orthorhombic phase shows a classical soft mode behavior up to x=0.17, supporting its correlation with the LTO to HTT transition. In the xx/yy polarization spectra of the superconducting concentrations new modes at ~150 and 370 cm^{-1} related to the symmetry breaking and a broad band at ~280 cm^{-1} are attributed to the charge ordering at temperatures well above T_c. At all temperatures studied a correlation has been found between the doping dependence of the transition temperature and the intensity of the bands at ~150, ~280, ~370 cm^{-1}, the intensity of the La/Sr mode, and the asymmetry of the apex phonon.