Fundamentale Korrelationen zwischen magnetischer Ordnung und itineranten Ladungsträgern in stark korrelierten Übergangsmetall-Oxiden

我们提出飞秒实验研究超快载流子自旋相互作用的强相关过渡金属氧化物，包括高温（高Tc）铜氧化物超导体。最近的非时间分辨的中子散射实验提供了证据的空间和时间的波动的电荷和反铁磁自旋顺序，其对高Tc配对机制的影响目前有争议。超快光学光谱学以前已经证明了通过其特征时间签名来辨别复杂多体系统（例如半导体）的实质成分的潜力，在线性光谱学中无法区分。本文提出的Cr_2O_3，La_2-xSr_xCuO_4和YBa_2Cu_3O_（7-d）的光学实验旨在以~ 100 fs的时间分辨率实时研究反铁磁自旋波（磁振子）的演化和相互关联以及掺杂载流子对其动力学的影响。我们提出的实验将采用泵浦-探测和四波混频技术，并将时间分辨磁二次谐波光谱首次扩展到反铁磁材料的研究。

We propose femtosecond experiments to study ultrafast carrierspin interactions in strongly correlated transition-metaloxides, including high-temperature (high-Tc) cuprate superconductors. Recent non-time-resolved neutron scattering experiments provide evidence for spatial and temporal fluctuations of charge and antiferromagnetic spin order, the influence of which on the high-Tc pairing mechanism is currently debated. Ultrafast optical spectroscopy has previously proven the potential to discern substantial ingredients of complex many-body systems (e.g. in semiconductors) by their characteristic temporal signature, undistinguishable in linear spectroscopy. The optical experiments on Cr2O3, La2-xSrxCuO4 and YBa2Cu3O7-d proposed here are designed to study in real-time, with ~ 100 fs time resolution, the evolution and mutual correlations of antiferromagnetic spin waves (magnons) and the influence of doped charge carriers on their dynamics. Our proposed experiments will employ pump-probe and four-wave mixing techniques and extend time-resolved magnetic second-harmonic spectroscopy for the first time to the study of antiferromagnetic materials.