Strong suppression of superconductivity by divalent ytterbium Kondo holes in CeCoIn5
Strong suppression of superconductivity by divalent ytterbium Kondo holes in CeCoIn5
复制标题
CeCoIn5 中二价镱近藤空穴对超导性的强烈抑制
DOI：
10.1103/physrevb.86.144526
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发表时间：
2012
影响因子：
3.7
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
M. Shimozawa;et al.
为了研究 Ce 基 Kondo 晶格中部分取代的 Yb 离子的性质，我们使用分子束外延技术制备了高质量的 CeYbCoIn 外延薄膜。我们发现 Yb 取代导致晶胞体积线性减小（表明 Yb 离子是二价的，在 CeYbCoIn 中形成近藤空穴），并导致超导性和近藤相干性受到强烈抑制。这些结果与霍尔效应的测量相结合，表明 Yb 离子在相干近藤晶格中充当非磁性杂质散射体，而没有严重抑制反铁磁涨落。这些结果与之前使用块状单晶进行的研究形成鲜明对比，后者声称 Yb 离子价态波动的重要性。目前的工作还强调了外延膜在研究近藤晶格的杂质效应中的适用性。
To study the nature of partially substituted Yb ions in a Ce-based Kondo lattice, we fabricated high quality CeYbCoInepitaxial thin films using molecular beam epitaxy. We find that the Yb substitution leads to a linear decrease of the unit cell volume—indicating that Yb ions are divalent, forming Kondo holes in CeYbCoIn—and leads to a strong suppression of the superconductivity and Kondo coherence. These results, combined with measurements of the Hall effect, indicate that Yb ions act as nonmagnetic impurity scatterers in the coherent Kondo lattice without serious suppression of the antiferromagnetic fluctuations. These results are in stark contrast to previous studies performed using bulk single crystals, which claim the importance of valence fluctuations of Yb ions. The present work also highlights the suitability of epitaxial films in the study of the impurity effect on the Kondo lattice.