Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Phys Rev Lett. 2011 Feb 11;106(6):067002. doi: 10.1103/PhysRevLett.106.067002. Epub 2011 Feb 10.
Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.
尽管母体的铁基磷化物和硫属化物是巡游反铁磁体，但仍广泛采用局域矩图来理解它们的磁性。我们从局域矩的角度研究了各种针对这种新型超导体提出的量子自旋模型的磁拉曼散射。这些模型在磁各向异性程度上存在很大差异，表现出截然不同的双磁振子拉曼响应。因此，双磁振子激发的光散射提供了对潜在自旋相互作用的稳健且独立的测量。与其他最近的实验结果一致，我们的结果表明这些体系中的磁各向异性可能较小。
