Reply to "Comment on newly found Charge Density Waves in infinite layer Nickelates''

TL;DR

This paper defends previous findings of charge density waves in NdNiO$_2$ thin films by providing resonant inelastic x-ray scattering evidence, countering recent comments that questioned their existence due to substrate reflections.

Contribution

It presents new energy-dependent resonant inelastic x-ray scattering data confirming the intrinsic nature of the CDW peak in NdNiO$_2$ films, clarifying previous ambiguities.

Findings

Resonant inelastic x-ray scattering shows a strong resonance at the CDW wavevector.

The observed scattering peak has an electronic origin with no detectable structural component.

Attempts to measure substrate peaks at I21 were unsuccessful.

Abstract

Charge density waves (CDW) have been reported in NdNiO$_2$ and LaNiO$_2$ thin films grown on SrTiO$_3$ substrates using Ni-$L_3$ resonant x-ray scattering in Refs. [1-3]. In their comment [arXiv:2306.15086] on these reports, Pelliciari et al. found no evidence for a CDW in a NdNiO$_2$ film by performing fixed-momentum energy-dependent measurements. Instead, they observed a nearby non-resonant scattering peak, attributed to the (101) substrate reflection, made accessible at Ni-$L_3$ due to third harmonic light contamination. Here we present fixed-momentum energy-dependent resonant inelastic x-ray scattering measurements across Ni-$L_3$ on NdNiO$_2$, used in the preceding study [1]. We see intrinsic Ni-$L_3$ energy profiles at all measured \textbf{Q} values, including a strong resonance effect at $\mathbf{Q}_\mathrm{CDW} = (-1/3, 0, 0.316)$ reciprocal lattice units. Attempts to measure the (101) substrate peak using third harmonic light at Ni-$L_3$ at I21, Diamond were unfruitful. Our results clearly demonstrate the electronic origin of the scattering peak published in Ref. [1] and lack of a detectable structural component in the peak.