A Correlated Route to Antiferromagnetic Spintronics
Universidad de Buenos Aires（布宜诺斯艾利斯大学）；CONICET–Universidad de Buenos Aires, Instituto de Física de Buenos Aires (IFIBA)（阿根廷国家科学研究委员会-布宜诺斯艾利斯大学，布宜诺斯艾利斯物理研究所）
Joel Bobadilla, Alberto Camjayi
备注：
Revised version. Expanded symmetry analysis and discussion of the connection with altermagnetic Hubbard models. Supplemental Material substantially extended, including the magnetic phase diagram, scattering-rate analysis, and a comparison with the paramagnetic solution
Antiferromagnets are attractive for spintronics owing to their vanishing net magnetization and ultrafast spin dynamics, yet their spin-compensated electronic structure has long confined them to passive roles. Here we identify a symmetry selection rule that overcomes this limitation: in a collinear antiferromagnet, a spin-polarized dc charge current requires the simultaneous breaking of particle--hole symmetry and of the equivalence between the two magnetic sublattices, either one alone leaving the polarization identically zero. We demonstrate the rule in the doped antiferromagnetic Hubbard model within dynamical mean-field theory: doping and a uniform magnetic field each break one of the two symmetries, and electronic correlations convert the resulting hierarchy of spin-dependent scattering rates into a sizable, field-tunable polarization of the charge current. The polarization is largest deep in the ordered phase and reverses sign at an emergent compensation point, not dictated by symmetry, at which the dominant conducting spin species is interchanged. In correlated altermagnetic Hubbard models, the same two symmetries are broken structurally, by the sublattice-alternating hopping pattern: the field-driven mechanism identified here and the altermagnetic one are two realizations of a single selection rule. Electronic correlations thus emerge as an active ingredient for spintronics in structurally conventional collinear antiferromagnets.
The route of frustrated cuprates from antiferromagnetic to ferromagnetic spin-1/2 Heisenberg chains: Li2ZrCuO4 as a missing link near the quantum critical point
Fractional antiferromagnetic skyrmion lattice induced by anisotropic couplings
磁Skyrmions是一种具有纳米级缠绕自旋织构的拓扑孤子，在自旋电子学中有着广泛的应用前景。到目前为止，已经在各种磁体中观察到Skyrmions，这些磁体表现出相邻自旋的几乎平行排列，但理论上，具有反平行相邻自旋的Skyrmions也是可能的。后者，反铁磁skyrmions，可以允许更灵活的控制相比，传统的铁磁skyrmions。在这里，通过结合中子散射和蒙特卡罗模拟，我们表明，一个分数反铁磁skyrmion晶格与初期meron字符是稳定的MnSc $_2$ S $_4$通过各向异性耦合。我们的工作表明，理论上提出的反铁磁skyrmion可以在实际材料中稳定，并代表了实现反铁磁skyrmion为基础的自旋电子器件的重要一步。
Picosecond creation of switchable optomagnets with giant photoinduced Kerr rotations in polar antiferromagnetic (Fe$_{1-x}$Zn$_{x}$)$_{2}$Mo$_{3}$O$_{8}$
具有长极化寿命和易于检测的信号的按需自旋取向是自旋电子学的最终目标。然而，在自旋极化的可控性和稳定性之间仍然存在权衡，等待重大突破。在这里，我们证明了可切换的光磁效应（Fe $_{1-x}$ Zn $_{x}$）$_{2}$ Mo $_{3}$ O $_{8}$，从中我们可以获得可调的磁化强度，从-40 $\%$到40 $\%$的饱和磁化强度，从零磁化强度在反铁磁状态下没有磁场。它可以通过利用圆偏振激光脉冲来激发极性反铁磁体中的自旋翻转跃迁，这些反铁磁体没有自旋倾斜，传统上在没有非常强的磁场的情况下难以控制。（Fe $_{1-x}$ Zn $_{x}$）$_{2}$ Mo $_{3}$ O $_{8}$中的自旋可控性源于其极性结构，该极性结构打破了晶体反转对称性，允许不同的原位$d$ - $d$跃迁用于选择性自旋翻转。通过化学掺杂，我们利用反铁磁态和亚铁磁态之间的相位竞争来增强和稳定光磁体效应，从而产生长寿命的光致克尔旋转。本研究在极性反铁磁体中创造了可切换的巨光磁效应，为反铁磁自旋电子学的功能勾画了一幅新的蓝图。
All-optical control of antiferromagnetic domains via an inverse optical magnetoelectric effect
RIKEN Center for Emergent Matter Science (CEMS)（RIKEN 新兴物质科学中心）；Institut für Festkörperforschung（固体研究所）；Department of Advanced Materials Science, The University of Tokyo（东京大学先进材料科学系）；Center for Electronic Correlations and Magnetism, University of Augsburg（奥格斯堡大学电子关联与磁性中心）；Tokyo College and department of Applied Physics, The University of Tokyo（东京大学东京学院与应用物理系）
