Metal–insulator transition and superconductivity in Hg-doped BaPb0.75Bi0.25O3
Metal–insulator transition and superconductivity in Hg-doped BaPb0.75Bi0.25O3
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DOI：
10.1016/j.jpcs.2010.10.037
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发表时间：
2011-05
影响因子：
4
通讯作者：
Yong Zhang;Y. L. Chen;C. H. Cheng;Y. Cui;Yong Zhao
中科院分区：
文献类型：
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作者：
Yong Zhang;Y. L. Chen;C. H. Cheng;Y. Cui;Yong Zhao
利用磁性测量、X射线粉末衍射（XRD）和X射线光电子能谱（XPS）研究了Hg掺杂对BaPb0.75Bi0.25O3（BaPb0.75−xHgxBi0.25O3，BPHBO）超导体超导电性、晶体结构和电子结构的影响。在较低的掺杂水平下，该系统是金属的和超导的。然而，当x>0.25时，Hg掺杂完全抑制了超导电性，当x>0.3时，随着Hg含量的进一步增加，超导电性恢复，显示出超导电性重入现象。XPS分析表明，BPHBO经历双金属绝缘体转变（MIT）在这两个超导点，这是伴随着晶格畸变，这表明他们可能是由Peierls转变驱动。第一个MIT可能是Mott跃迁，而第二个MIT可能是由于带填充效应和电荷不成比例状态的修改之间的竞争。
The effects of mercury doping on the superconductivity, crystal structure, and electronic structure have been investigated in Hg-doped BaPb0.75Bi0.25O3(BaPb0.75−xHgxBi0.25O3, BPHBO) by magnetic measurement, powder X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS). At lower doping levels, the system is metallic and superconducting. However, the superconductivity is fully suppressed by Hg doping at x>0.25 and recovered with further increase in Hg content at x>0.3, showing a superconductivity reentrant phenomenon. XPS analysis reveals that BPHBO experiences dual metal–insulator transitions (MITs) at these two superconductivity points, which are accompanied by lattice distortions, suggesting that they may be driven by Peierls transitions. The first MIT may be a Mott-transition, while the second may be due to competition between the band filling effect and modification of the charge-disproportionate state.