Rare-earth transition-metal pnictides: Heavy -fermion behavior versus magnetism and superconductivity

稀土过渡金属磷族元素：重费米子行为与磁性和超导性

• 批准号: 179402299
• 负责人: Professor Dr. Clemens Laubschat
• 金额: --
• 依托单位: Arbeitsgruppe Photoelektronenspektroskopie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/179402299?language=en
• 关键词: Rare; earth; transition; metal; pnictides

In Ce-based iron-pnictides, mixed-valent or heavy-fermion behavior of the Ce 4f states is in direct competition to other electron-correlation effects like magnetic order, superconductivity, and spin-density wave (SDW) formation that lead to interesting material properties which depend critically on parameters like chemical composition or external pressure. The interplay of these correlation phenomena will be studied by means of angle and spin-resolved photoelectron (PE) spectroscopy with synchrotron radiation on the basis of structurally well-characterized single-crystalline samples. Momentum (k-vector) dependent interactions between Ce 4f and particularly Fe 3d -derived bands are expected to lead to dispersions and energy-splittings of the resulting quasi-particle bands that determine the Fermi surfaces and may be visualized by means of PE. Experimental data from single-crystalline samples will be taken as a function of temperature and chemical composition and will be discussed within an approach to the periodic Anderson-model (PAM) that is solved by dynamical meanfield theory (DMFT) using non-crossing approximation (NCA) as impurity solver and results of band-structure calculations for the non-hybridized valence-band (VB) states.

在基于 Ce 的铁磷族化合物中，Ce 4f 态的混合价或重费米子行为与其他电子相关效应（如磁序、超导性和自旋密度波 (SDW) 形成）直接竞争，这些效应导致有趣的材料特性，这些特性关键取决于化学成分或外部压力等参数。这些相关现象的相互作用将在结构良好表征的单晶样品的基础上，通过同步加速器辐射的角度和自旋分辨光电子（PE）光谱来研究。 Ce 4f 和特别是 Fe 3d 衍生带之间的动量（k 向量）依赖性相互作用预计会导致所产生的准粒子带的色散和能量分裂，从而确定费米表面并可以通过 PE 进行可视化。来自单晶样品的实验数据将被视为温度和化学成分的函数，并将在周期性安德森模型（PAM）的方法中进行讨论，该方法使用非交叉近似（NCA）作为杂质求解器通过动态平均场理论（DMFT）求解，以及非杂化价带（VB）态的能带结构计算结果。