CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2011 Nov 18;107(21):216403. doi: 10.1103/PhysRevLett.107.216403.
Our inelastic neutron scattering study of spin excitations in iron telluride reveals remarkable thermal evolution of the collective magnetism. In the temperature range relevant for the superconductivity in FeTe(1-x)Se(x) materials, where the local-moment behavior is dominated by liquidlike correlations of emergent spin plaquettes, we observe unusual, marked increase of magnetic fluctuations upon heating. The effective spin per Fe at T ≈ 10 K, in the phase with weak antiferromagnetic order, corresponds to S ≈ 1, consistent with the recent analyses that emphasize importance of Hund's coupling [K. Haule and G. Kotliar, New J. Phys. 11, 025021 (2009).]. However, it grows to S ≈ 3/2 in the high-T disordered phase, suggestive of the Kondo-type behavior, where local magnetic moments are entangled with the itinerant electrons.
我们对铁碲化物中自旋激发的非弹性中子散射研究揭示了集体磁性的显著热演化。在与 FeTe(1-x)Se(x) 材料中超导相关的温度范围内，其中局域磁矩行为由新兴的自旋棋盘格的液态相关所主导，我们观察到加热时磁涨落异常显著的增加。在具有弱反铁磁序的相中，在 T ≈ 10 K 时，每个 Fe 的有效自旋对应于 S ≈ 1，这与最近强调 Hund 耦合重要性的分析一致[K. Haule 和 G. Kotliar, New J. Phys. 11, 025021 (2009).]。然而，在高温无序相中，它增长到 S ≈ 3/2，表明存在类似于 Kondo 型的行为，其中局域磁矩与巡游电子纠缠在一起。
