The magnetic moment in van der Waals (vdW) materials containing 3d transition metals originates from unpaired d-electron spins and their interaction with surrounding ligands. The interplay between exchange interactions and magnetic anisotropy stabilizes long-range ordering of such moments. The compound CuCrP2S6 (CCPS) presents an interesting class of vdW solids where the coupling of Cr3+ moments and ordering of Cu1+ ions give rise to a multiferroic ground state. Here we investigate the spin dynamics of Cr3+ ions in CCPS through magnetization and broadband as well as single sub-THz magnetic resonance measurements. The orbital moment of Cr3+ is quenched under the octahedral crystal field of surrounding chalcogen ions, resulting in negligible magnetic anisotropy-a feature common to Cr-based vdW antiferromagnets (AFM). Resonance spectra over a wide frequency-field-temperature range reveal quasi-2D AFM dynamics governed mainly by isotropic Cr-Cr exchange interactions, which determine the magnetic order, spin reorientation, and damping. Sub-THz resonance spectra also uncover a field-induced ferromagnetic polarization, highlighting the universal role of Cr-Cr exchange in layered Cr compounds. Moreover, persistent magnetic correlations far above the Néel temperature (TN ~ 32 K) points to short-range magnetic order in CCPS and motivates future studies of a possible interplay between AFM and antiferroelectric orders. These results establish CCPS as an exemplary system for exploring 2D magnetism and electric-field-tunable spintronic functionalities in layered multiferroics.
Spin-flip optical excitations in van der Waals antiferromagnet CrPS$_4$
National University of Singapore（新加坡国立大学）；University of Chemistry and Technology Prague（布拉格化工大学）；Institute of Physics, Charles University（查理大学物理研究所）；Department of Materials Science and Engineering, National University of Singapore（新加坡国立大学材料科学与工程系）；Faculty of Physics, University of Warsaw（华沙大学物理学院）
Engineering photomagnetism in collinear van der Waals antiferromagnets
Radboud University, Institute for Molecules and Materials（拉德堡德大学分子与材料研究所）；HFML-FELIX；Institute of Physics, University of Amsterdam（阿姆斯特丹大学物理研究所）；Department of Physics, Technische Universität Dortmund（多特蒙德工业大学物理系）；Research Center Future Energy Materials and Systems（未来能源材料与系统研究中心）；King’s College London, Theory and Simulation of Condensed Matter（伦敦国王学院凝聚态理论模拟）
Correlation between Exciton Dynamics and Spin Structure in van der Waals Antiferromagnet NiPS3
Department of Physics, Xiamen University（厦门大学物理系）；Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University（南京大学化学化工学院介观化学重点实验室）；Mork Family Department of Chemical Engineering and Materials Science, University of Southern California（南加州大学莫克家族化学工程与材料科学系）；Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, Fujian Normal University（福建师范大学福建省面向先进材料的化学工程重点实验室）
Selective Octahedral Accommodation of Cr$^{3+}$ and Weak Magnetic Connectivity in the Sugilite Analogue KNa$_2$Cr$_2$Li$_3$Si$_{12}$O$_{30}$
Graduate School of Engineering, Tokyo University of Agriculture and Technology（东京农工大学大学院工学研究科）；The Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）
Kitaev interactions in the van der Waals antiferromagnet VBr3
Fudan University（复旦大学）；J-PARC Center（日本原子力研究开发机构J-PARC中心）；Shanghai Research Center for Quantum Sciences（上海量子科学研究中心）；Institute of Nanoelectronics and Quantum Computing, Fudan University（复旦大学纳米电子与量子计算研究所）
研究通过非弹性中子散射揭示了van der Waals反铁磁体VBr3中的Kitaev相互作用，并表明配体工程可调节Kitaev相互作用。
First-principles description of van der Waals-bonded spin-polarized systems using vdW-DF$+U$ method---application to solid oxygen at low pressure
O $_2$的分子固相，特别是其基态反铁磁绝缘相的描述，是众所周知的，在传统的本地和半本地密度泛函近似中使用的密度泛函理论的Kohn-Sham形式主义是相当不令人满意的。最近发展的范德瓦尔斯泛函，考虑到非局部相关性也表现出低于标准的性能在这方面。困难在于分子晶体中反铁磁和铁磁分子对之间的范德华相互作用和交换耦合之间的微妙平衡。在这里，我们报告说，DFT $+U$的方法结合使用的vdW-DF功能在这方面表现得令人惊讶的好，并讨论这种行为背后的推理。我们也应用这种方法来研究最近报道的磁场诱导的固体O $_2$的$θ$相。
A van der Waals antiferromagnetic topological insulator with weak interlayer magnetic coupling
磁性拓扑绝缘体（TI）是研究量子反常霍尔效应（QAH）和马约拉纳模（Majorana模）等量子现象的重要材料平台，其成功的材料实现对我们的基本认识和潜在的技术革命至关重要。通过实现具有交替的七层[MnBi 2 Te 4]和五层[Bi 2 Te 3]层的体材料MnBi 4 Te 7，我们表明它在平面内是铁磁的，但沿c轴是反铁磁的，在2 K时的面外饱和场为~ 0.22 T.我们的角分辨光电子能谱测量和第一性原理计算进一步证明了MnBi 4 Te 7是一个Z2反铁磁TI与两种类型的表面状态与[MnBi 2 Te 4]或[Bi 2 Te 3]终止，分别。此外，其超晶格性质可以通过剥离使[MnBi 2 Te 4]和[Bi 2 Te 3]层的各种异质结构成为可能。因此，MnBi_4Te_7的低饱和场和超晶格性质使其成为研究丰富涌现现象的理想体系。
Weyl points enabling significant enhancement of thermoelectric performance in an antiferromagnetic van der Waals metal GdTe3
Key Laboratory of Material Physics, Ministry of Education, School of Physics, Zhengzhou University（郑州大学物理学院教育部材料物理重点实验室）；Department of Physics, State key laboratory of quantum functional materials, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology (SUSTech)（南方科技大学物理系量子功能材料国家重点实验室和广东省基础研究中心量子科学卓越中心）；Hefei National Laboratory, University of Science and Technology of China（中国科学技术大学合肥国家实验室）；Collaborative Innovation Center of Advanced Microstructures, Nanjing University（南京大学先进微结构协同创新中心）
