Conduction-Band Electronic States of YbInCu_4 Studied by Photoemission and Soft X-ray Absorption Spectroscopies
Conduction-Band Electronic States of YbInCu_4 Studied by Photoemission and Soft X-ray Absorption Spectroscopies
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光电发射和软X射线吸收光谱研究YbInCu_4的导带电子态
DOI：
10.1103/physrevb.84.115143
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发表时间：
2011
影响因子：
3.7
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
Y.Utsumi;et al
用Cu2的含温硬X射线光电子能谱(HX-PES)、Cu2核在V附近吸收区的软X射线吸收谱(XAS)和Cu2吸收边价带的软X射线光电子能谱(SX-PES)研究了典型价态过渡化合物YbInCu2的导带电子态。随着价态转变温度的降低，我们发现：(1)HX-PES谱中的Cu2峰和In峰分别向低结合能侧移动了40 meV和30 meV；(2)XAS谱中Cu2主吸收峰的能量位置向高光子能量侧移动了100 meV，在Cu2主吸收峰下方出现了肩状结构；(3)CuAuger谱的强度突然增强。这些实验结果表明，CB导出态密度的费米能级向低结合能侧移动。我们从Cb态到Yb4态的电荷转移描述了YbInCuin的价态转变。
We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCuby means of temperature-dependent hard x-ray photoemission spectroscopy (HX-PES) of the Cu 2and In 3core states taken atkeV, soft x-ray absorption spectroscopy (XAS) of the Cu 2core absorption region aroundeV, and soft x-ray photoemission spectroscopy (SX-PES) of the valence band at the Cu 2absorption edge ofeV. With decreasing temperature below the valence transition atK, we have found that (1) the Cu 2and In 3peaks in the HX-PES spectra exhibit the energy shift toward the lower binding-energy side by40 and30 meV, respectively, (2) an energy position of the Cu 2main absorption peak in the XAS spectrum is shifted toward higher photon-energy side by100 meV, with an appearance of a shoulder structure below the Cu 2main absorption peak, and (3) an intensity of the CuAuger spectrum is abruptly enhanced. These experimental results suggest that the Fermi level of the CB-derived density of states is shifted toward the lower binding-energy side. We have described the valence transition in YbInCuin terms of the charge transfer from the CB to Yb 4states.