Different evolution of the intrinsic gap in strongly correlated SmB6 in contrast to YbB_<12>
Different evolution of the intrinsic gap in strongly correlated SmB6 in contrast to YbB_<12>
复制标题
与 YbB_<12> 相比，强相关 SmB6 中内在能隙的不同演变
DOI：
10.1088/1367-2630/15/4/043042
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
A. Sekiyama他18人
中科院分区：
文献类型：
--
作者：
J. Yamaguchi;A. Sekiyama他18人
利用光电子能谱技术，详细研究了强关联合金Sm 1− x Eu x B 6和Y B 1− x Lu x B 12在~ 8000 eV以及7和8.4 eV下费米能级附近的光谱函数随温度和稀土原子掺杂的依赖关系。结果发现，Sm 1− x Eu x B 6的4f晶格相干性和本征能隙至少在x = 0.15的Eu取代之前是稳定的，而Y B 1− x Lu x B 12的4f晶格相干性和本征能隙在x= 0.125的Lu取代时已经崩溃。至于费米能级附近的光谱形状在低温下的温度依赖性，而对比的结果之间观察到YbB 12和SmB 6。对于特征温度T* 为80 K的YbB 12，在15 K以下，差距形状不发生变化，而对于特征温度T* 为140 K的SmB 6，在15 K以下，超过差距的峰进一步增大。在SmB 6和YbB 12之间，本征能隙附近的光谱的温度依赖性明显不同，尽管这两种材料到目前为止被归类为同一种强相关半导体。表面贡献的可能性进行了讨论SmB 6。
Dependence of the spectral functions near the Fermi level on temperature and rare-earth atom doping was studied in detail for strongly correlated alloys Sm 1− x Eu x B 6 and Yb 1− x Lu x B 12 by photoelectron spectroscopy at∼ 8000 eV as well as at 7 and 8.4 eV. It was found that the 4f lattice coherence and intrinsic gap are robust for Sm 1− x Eu x B 6 at least up to the Eu substitution of x= 0.15 while both collapse by Lu substitution already at x= 0.125 for Yb 1− x Lu x B 12. As for the temperature dependence of the spectral shapes near the Fermi level at low temperatures, rather contrasting results were observed between YbB 12 and SmB 6. Although the gap shape does not change below 15 K for YbB 12 with the characteristic temperature T* of 80 K, the spectral shape of SmB 6 with a T* of 140 K shows that the peak beyond the gap is further increased below 15 K. The temperature dependence of the spectra near the intrinsic gap is clearly different between SmB 6 and YbB 12, although both materials have so far been categorized in the same kind of strongly correlated semiconductor. The possibility of the surface contribution is discussed for SmB 6.