Resonant Raman scattering in mercurate single crystals

TL;DR

This study investigates resonant electronic Raman scattering in optimally doped Hg-based cuprate superconductors, revealing insights into their gap symmetry and universal energy scale behavior across different crystal structures.

Contribution

It provides the first detailed analysis of resonant Raman scattering in Hg-1201 and Hg-1223, highlighting the d-wave gap symmetry and the universal behavior of two energy scales in cuprates.

Findings

Evidence for d-wave superconducting gap symmetry in Hg-1201.

Identification of two energy scales with universal behavior in cuprates.

The A1g peak is not directly related to the superconducting gap amplitude.

Abstract

We report resonant electronic Raman scattering in optimally doped single layer HgBa$_2$CuO$_{4+\delta}$ (Hg-1201) and trilayer HgBa$_2$Ca$_2$Cu$_3$O$_{8+\delta}$ (Hg-1223) single crystals. Analysis of the $B_{1g}$ and B$_{2g}$ channels in the superconducting state of Hg-1201 advocates for a gap having d-wave symmetry. In addition a resonant study $B_{1g}$ pair-breaking peak and the $A_{1g}$ peak suggests that the $A_{1g}$ peak is not directly related to the d-wave superconducting gap amplitude. Comparison with trilayer Hg-1223 demonstrates the universal behavior of this two energy scales in optimally doped cuprates.