Physics and Astronomy, Ames Laboratory
Journal or Book Title
Physical Review B
Inelastic neutron scattering from superconducting (SC) Ba(Fe0.926Co0.074)2As2 reveals anisotropic and quasi-two-dimensional (2D) magnetic excitations close to QAFM=(1212) - the 2D antiferromagnetic (AFM) wave vector of the parent BaFe2As2 compound. The correlation length anisotropy of these low-energy fluctuations is consistent with spin nematic correlations in the J1−J2 model with J1/J2∼1. The spin resonance at ∼8.3 meV in the SC state displays the same anisotropy. The anisotropic fluctuations experimentally evolve into two distinct maxima only along the direction transverse to QAFM above ∼80 meV indicating unusual quasipropagating excitations.
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Li, H.-F.; Broholm, C.; Vaknin, David; Fernandes, R. M.; Abernathy, D. L.; Stone, M. B.; Pratt, D. K.; Tian, W.; Qiu, Y.; Ni, Ni; Diallo, S. O.; Zarestky, J. L.; Bud’ko, Sergey L.; Canfield, Paul C.; and McQueeney, Robert J., "Anisotropic and quasipropagating spin excitations in superconducting Ba(Fe0.926Co0.074)(2)As-2" (2010). Physics and Astronomy Publications. 699.