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

在基于Ce的铁磷属元素化物中，Ce 4f态的混合价态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，这些效应导致了有趣的材料特性，这些特性严重依赖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通过角度和自旋分辨光电子（PE）光谱与同步辐射的基础上，结构良好的特点单晶样品进行研究。动量（k-矢量）之间的依赖相互作用的Ce 4f和特别是Fe 3d衍生的带预计将导致色散和能量分裂的准粒子带，确定费米表面，并可以可视化的PE。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）的方法内进行讨论，该模型通过动态平均场理论（DMFT）使用非交叉近似（NCA）作为杂质求解器和非杂化价带（VB）状态的能带结构计算结果来求解。

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.