Stripe Antiferromagnetic Spin Fluctuations in SrCo$_{2}$As$_{2}$

TL;DR

This study reveals stripe antiferromagnetic spin fluctuations in SrCo₂As₂, similar to iron arsenides, indicating a potential for unconventional superconductivity driven by spin fluctuations in cobalt-based compounds.

Contribution

It provides the first inelastic neutron scattering evidence of stripe AFM spin fluctuations in SrCo₂As₂, expanding the understanding of magnetic behaviors in cobalt arsenides.

Findings

Stripe AFM spin fluctuations are observed at Q_AF M=(1/2,1/2,1).

SrCo₂As₂ exhibits a large energy scale of spin fluctuations.

Results suggest a commonality of stripe AFM magnetism in arsenide compounds.

Abstract

Inelastic neutron scattering measurements of paramagnetic SrCo$_{2}$As$_{2}$ at T=5 K reveal antiferromagnetic (AFM) spin fluctuations that are peaked at a wavevector of $\textbf{Q}_{\mathrm{AFM}}=(1/2,1/2,1)$ and possess a large energy scale. These stripe spin fluctuations are similar to those found in $A$Fe$_{2}$As$_{2}$ compounds, where spin-density wave AFM is driven by Fermi surface nesting between electron and hole pockets separated by $\textbf{Q}_{\mathrm{AFM}}$. SrCo$_{2}$As$_{2}$ has a more complex Fermi surface and band structure calculations indicate a potential instability towards either a ferromagnetic or stripe AFM ground state. The results suggest that stripe AFM magnetism is a general feature of both iron and cobalt-based arsenides and the search for spin fluctuation-induced unconventional superconductivity should be expanded to include cobalt-based compounds.