Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Sci Rep. 2017 Aug 14;7(1):8003. doi: 10.1038/s41598-017-07286-6.
Fe-K X-ray emission spectroscopy measurements reveal an asymmetric doping dependence of the magnetic moments μ in electron- and hole-doped BaFeAs. At low temperature, μ is nearly constant in hole-doped samples, whereas it decreases upon electron doping. Increasing temperature substantially enhances μ in the hole-doped region, which is naturally explained by the theoretically predicted crossover into a spin-frozen state. Our measurements demonstrate the importance of Hund's-coupling and electronic correlations, especially for hole-doped BaFeAs, and the inadequacy of a fully localized or fully itinerant description of the 122 family of Fe pnictides.
Fe-K X 射线发射光谱测量揭示了电子和空穴掺杂 BaFeAs 中磁矩 μ 的不对称掺杂依赖性。在低温下，μ 在空穴掺杂样品中几乎保持不变，而在电子掺杂时则减小。随着温度的升高，空穴掺杂区域中的 μ 会大大增强，这可以通过理论预测的进入自旋冻结状态的交叉来自然解释。我们的测量结果表明了 Hund 耦合和电子相关的重要性，特别是对于空穴掺杂的 BaFeAs，以及对 Fe 磷化物 122 族的完全局域或完全巡游描述的不充分性。
