Heavy fermion material: Ce versus Yb case
Heavy fermion material: Ce versus Yb case
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重费米子材料：Ce 与 Yb 案例
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
H. Harima
中科院分区：
文献类型：
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作者：
J. Flouquet;H. Harima
重费米子化合物是一种复杂的体系，但也是研究不同基态之间量子临界性的优良材料。在这里，特别注意的是磁和价不稳定性之间的相互作用，可以通过调整系统的压力或磁场交叉或接近。与传统的稀土磁性或经典的s波超导相反，强耦合可能会发生自旋或电荷动力学的剧烈变化。对Ce材料的测量已经给出了具有明确关键因素的合理基础;他们指出，接近磁临界或价临界时会出现意想不到的现象，如非常规超导性，非费米液体行为和磁场下重新进入现象的可能性。Yb重费米子化合物生长的最新进展给出了价态和磁涨落之间明确相互作用的前景，以及进入新情况的可能性，例如在单一双重晶场基态内的价态跃迁。
Heavy fermion compounds are complex systems but excellent materials to study quantum criticality with the switch of different ground states. Here a special attention is given on the interplay between magnetic and valence instabilities which can be crossed or approached by tuning the system by pressure or magnetic field. By contrast to conventional rare earth magnetism or classical s wave superconductivity, strong couplings may occur with drastic changes in spin or charge dynamics. Measurements on Ce materials give already a sound basis with clear key factors; they have pointed out that close to a magnetic or a valence criticality unexpected phenomena such as unconventional superconductivity, non Fermi liquid behaviour and the possibility of re-entrance phenomena under magnetic field. Recent progresses in the growth of Yb heavy fermion compounds give the perspectives of clear interplays between valence and magnetic fluctuations and also the possibility to enter in new situations such as valence transitions inside a sole doublet crystal field ground state.