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arXiv 1409.6571cond-mat.str-elcond-mat.mtrl-sci
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ARPES对YbB6(001)金属状态的深入了解:E(k)色散、时间变化和空间变化

ARPES insights on the metallic states of YbB6(001): E(k) dispersion, temporal changes and spatial variation

Emmanouil Frantzeskakis, Nick de Jong, Jiuxing Zhang, Xin Zhang, Zhi Li, Chaolong Liang, Yang Wang, Andrei Varykhalov, Yingkai Huang, Mark S. Golden

摘要:

本文报道了YbB $_{6}$(001)解理面的高分辨角分辨光电子能谱学(ARPES)研究结果。我们观察到两种类型的良好分辨的金属状态,其费米轮廓包围的时间反演不变动量的Yb $_{6}$(001)表面布里渊区,其完整的(E,$k$)色散关系可以测量完全从其余的电子结构的状态未掩蔽。虽然这些金属态的二维特征被证实缺乏面外色散,但在这些实验中揭示了两个新的方面。首先,这些状态不像在狄拉克点交叉的相反的线速度的两个分支,而是直接的抛物线,其终止于具有清晰带底的高结合能。第二,这些状态是敏感的YbB $_{6}$表面的时间依赖性的变化在真空条件下。这些来自解理YbB $_{6}$表面的数据也显示了电子结构的空间变化,加上这一事实,似乎一方面理想化YbB $_{6}$(001)晶体截断的理论预期与另一方面来自真实解理表面的ARPES数据之间几乎没有共同之处。

英文摘要:

We report high resolution Angle Resolved PhotoElectron Spectroscopy (ARPES) results on the (001) cleavage surface of YbB$_{6}$, a rare-earth compound which has been recently predicted to host surface electronic states with topological character. We observe two types of well-resolved metallic states, whose Fermi contours encircle the time-reversal invariant momenta of the YbB$_{6}$(001) surface Brillouin zone, and whose full (E,$k$)-dispersion relation can be measured wholly unmasked by states from the rest of the electronic structure. Although the two-dimensional character of these metallic states is confirmed by their lack of out-of-plane dispersion, two new aspects are revealed in these experiments. Firstly, these states do not resemble two branches of opposite, linear velocity that cross at a Dirac point, but rather straightforward parabolas which terminate to high binding energy with a clear band bottom. Secondly, these states are sensitive to time-dependent changes of the YbB$_{6}$ surface under ultrahigh vacuum conditions. Adding the fact that these data from cleaved YbB$_{6}$ surfaces also display spatial variations in the electronic structure, it appears there is little in common between the theoretical expectations for an idealized YbB$_{6}$(001) crystal truncation on the one hand, and these ARPES data from real cleavage surfaces on the other.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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