Monday, June 24, 2013

1306.5174 (W. Jayasekara et al.)

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

W. Jayasekara, Y. Lee, Abhishek Pandey, G. S. Tucker, A. Sapkota, J. Lamsal, S. Calder, D. A. Abernathy, J. Niedziela, B. N. Harmon, A. Kreyssig, D. Vaknin, D. C. Johnston, A. I. Goldman, R. J. McQueeney
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.
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