Quenched Magnon excitations by oxygen sublattice reconstruction in (SrCuO$_2$)$_n$/(SrTiO$_3$)$_2$ superlattices

TL;DR

This study investigates how structural reconstruction in SrCuO$_2$/SrTiO$_3$ superlattices affects magnon excitations, revealing that partial reconstruction quenches magnons at the $ abla$-point, unlike charge impurities in doped cuprates.

Contribution

It demonstrates that oxygen sublattice reconstruction in superlattices causes magnon quenching, a novel insight into magnetic excitation behavior in these materials.

Findings

Partial reconstruction occurs at n=5, affecting magnetic properties.

Magnon excitations are quenched at the $ abla$-point due to reconstructed Cu plaquettes.

Charge impurities do not cause similar magnon quenching.

Abstract

The recently discovered structural reconstruction in the cuprate superlattice (SrCuO$_2$)$_n$/(SrTiO$_3$)$_2$ has been investigated across the critical value of $n=5$ using resonant inelastic x-ray scattering (RIXS). We find that at the critical value of $n$, the cuprate layer remains largely in the bulk-like two-dimensional structure with a minority of Cu plaquettes being reconstructed. The partial reconstruction leads to quenching of the magnons starting at the $\Gamma$-point due to the minority plaquettes acting as scattering points. Although comparable in relative abundance, the doped charge impurities in electron-doped cuprate superconductors do not show this quenching of magnetic excitations.