Yang Yi-feng, Fisk Zachary, Lee Han-Oh, Thompson J D, Pines David
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Nature. 2008 Jul 31;454(7204):611-3. doi: 10.1038/nature07157.
The origin of magnetic order in metals has two extremes: an instability in a liquid of local magnetic moments interacting through conduction electrons, and a spin-density wave instability in a Fermi liquid of itinerant electrons. This dichotomy between 'local-moment' magnetism and 'itinerant-electron' magnetism is reminiscent of the valence bond/molecular orbital dichotomy present in studies of chemical bonding. The class of heavy-electron intermetallic compounds of cerium, ytterbium and various 5f elements bridges the extremes, with itinerant-electron magnetic characteristics at low temperatures that grow out of a high-temperature local-moment state. Describing this transition quantitatively has proved difficult, and one of the main unsolved problems is finding what determines the temperature scale for the evolution of this behaviour. Here we present a simple, semi-quantitative solution to this problem that provides a basic framework for interpreting the physics of heavy-electron materials and offers the prospect of a quantitative determination of the physical origin of their magnetic ordering and superconductivity. It also reveals the difference between the temperature scales that distinguish the conduction electrons' response to a single magnetic impurity and their response to a lattice of local moments, and provides an updated version of the well-known Doniach diagram.
一是通过传导电子相互作用的局域磁矩液体中的不稳定性，二是巡游电子费米液体中的自旋密度波不稳定性。“局域磁矩”磁性和“巡游电子”磁性之间的这种二分法让人联想到化学键研究中存在的价键/分子轨道二分法。铈、镱和各种5f元素的重电子金属间化合物类别跨越了这两个极端，在低温下具有巡游电子磁特性，这种特性由高温局域磁矩状态演变而来。定量描述这种转变已被证明很困难，主要未解决的问题之一是找出决定这种行为演变温度尺度的因素。在此，我们给出了这个问题的一个简单半定量解决方案，该方案为解释重电子材料的物理性质提供了一个基本框架，并为定量确定其磁有序和超导性的物理起源提供了前景。它还揭示了区分传导电子对单个磁性杂质的响应和对局域磁矩晶格的响应的温度尺度之间的差异，并给出了著名的多尼亚克图的更新版本。
