We report a comprehensive Raman study of the phonon behaviour in PdSe$_2$ in the temperature range of 5 K to 300 K. A remarkable change in the Raman spectrum is observed at 120 K: a significant enhancement of the out-of-plane phonon A$^{1}_{g}$ mode, accompanied by a suppression of the in-plane A$^{2}_{g}$ and B$^{2}_{1g}$ modes. This intriguing behavior is attributed to a temperature-dependent resonant excitation effect. The results are supported by density functional theory (DFT) calculations, which demonstrate that the electron-phonon coupling for the phonon modes varies and is strongly associated with the relevant electronic states. Furthermore, nonlinear frequency shifts are identified in all modes, indicating the decay of an optical phonon into multiple acoustic phonons. The study of Raman emission reported here, complemented by linear optical spectroscopy, reveals an unexpected scenario for the vibrational properties of PdSe$_2$ that holds substantial promise for future applications in PdSe$_2$-based optoelectronics.
Phonon dispersion, Raman spectra and evidence for spin-phonon coupling in MnV$_2$O$_4$ from first-principles
尖晶石结构中的MnV $_2$ O $_4$已知表现出耦合的轨道和自旋有序，并且其拉曼光谱在其低温相中显示出有趣的异常。为了解释这种行为，涉及耦合自旋和声子的目标，我们确定在这里的自旋-声子耦合MnV $_2$ O $_4$从其声子谱的理论分析和它们的依赖于自旋有序和电子相关性，从第一性原理密度泛函理论计算。使用这些在分析的基础上的朗道类理论，我们发现的机制，在其低温阶段观察到的拉曼异常。
Giant phonon anomalies in the pseudo-gap phase of TiOCl
本文报道了自旋为1/2的量子磁体TiOCl的红外和拉曼光谱结果。在声子谱的温度依赖性中发现了巨大的异常，这暗示了电子自由度与晶格的不寻常耦合。这些异常发展在一个广泛的温度间隔，这表明存在一个扩展的波动制度。这定义了一个伪能隙相，其特征在于局部自旋能隙。在100 K以下，维度交叉导致二聚基态，自旋能隙约为2 $Δ_{spin}\approx$ ~430 K.
Possible observation of the signature of the bad metal phase and its crossover to a Fermi liquid in K(BEDT-TTF)2Cu(NCS)2 bulk and nanoparticles by Raman scattering
Pressure induced structural phase transition and magneto-elastic coupling in Eu doped LaCrO$_3$
Indian Institute of Science Education and Research Kolkata（印度科学教育研究所加尔各答分校）；National Centre for High-Pressure Studies, Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata（印度科学教育研究所加尔各答分校物理科学学院高压研究中心）；Iowa State University（爱荷华州立大学）；IMPMC, Sorbonne Université, CNRS, MNHN（索邦大学、法国国家科学研究中心、法国国家自然历史博物馆巴黎矿物起源与演化实验室）
Lattice dynamics and structural correlations in antiferromagnet SrLaCoNbO$_6$ double perovskite
Ames National Laboratory, U.S. Department of Energy, Iowa State University（艾姆斯国家实验室）；Department of Physics, Indian Institute of Technology Delhi（德里印度理工学院物理系）；School of Physics, The University of New South Wales (UNSW)（新南威尔士大学物理学院）
Phonon anomalies and critical scaling in the spin-$1/2$ trimer chain Na$_2$Cu$_3$Ge$_4$O$_{12}$
Indian Institute of Technology Kharagpur（印度理工学院卡拉格普尔分校）；Bhabha Atomic Research Centre（巴巴原子研究中心）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Indian Institute of Technology Roorkee（印度理工学院鲁尔基分校）
Multiorbital character of the density wave in trilayer nickelate superconductors
Max-Planck-Institute for Solid State Research（马克斯·普朗克固体研究所）；Facultad de Ciencias Exactas, Ingeniería y Agrimensura and Instituto de Física Rosario (UNR-CONICET)（罗萨里奥大学精确科学、工程与测量学院及罗萨里奥物理研究所（UNR-CONICET））；RIKEN Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)（理化学研究所跨学科理论与数学科学中心 (iTHEMS)）
Orbital Dimerization and Dynamic Jahn-Teller Effect in NaTiSi$_2$O$_6$
本文用Raman散射技术研究了辉石化合物NaMSi $_2$ O $_6$（M=Ti，V，Cr）的两种相变。在准一维S=1/2系统NaTiSi $_2$ O $_6$中，我们观察到了反常的高温声子展宽，以及在210 K的相变中声子能量和线宽的大幅度变化。声子异常起源于轨道有序无序相变和这些结果-结合理论的考虑-表明，高温动力学Jahn-Teller相的NaTiSi $_2$ O $_6$表现出自发破坏的平移对称性的二聚化，Jahn-Teller扭曲，轨道有序状态下形成的自旋价键。在S=1的NaVSi $_2$ O $_6$的轨道自由度被强烈抑制，磁激发在海森堡模型中得到很好的描述，表明在T $_N$ = 19 K时，该系统反铁磁有序。
Temperature-driven sodium-ion dynamical-to-static crossover in the zig-zag ordered phase of Na$_{0.5}$CoO$_2$
Beijing Academy of Quantum Information Sciences（北京量子信息科学研究院）；Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院人工结构与量子控制教育部重点实验室）；School of Physical Science and Technology, Lanzhou University（兰州大学物理科学与技术学院）；International Center for Quantum Materials, School of Physics, Peking University（北京大学物理学院物质科学量子创新中心）；Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所北京凝聚态物理国家实验室）
Interplay of phonons, intertwined density waves, and induced spin density wave in trilayer nickelates Pr4-xLaxNi3O10
Indian Institute of Technology Mandi（印度理工学院曼迪分校）；Indian Institute of Science Education and Research Pune（印度科学教育研究所浦那分校）；Indian Institute of Technology Kanpur（印度理工学院坎普尔分校）
