Hybridization and correlation effects in the photoemission spectra of RNi2 (R=Ce, Pr, and Nd).
Hybridization and correlation effects in the photoemission spectra of RNi2 (R=Ce, Pr, and Nd).
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DOI：
10.1103/physrevb.49.16248
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发表时间：
1994-06
期刊：
影响因子：
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通讯作者：
Jeongsoo Kang;J. H. Hong;D. W. Hwang;J. I. Jeong;S. D. Choi;C. J. Yang;Youngnae Lee;C. G. Olson;Kicheon Kang;B. I. Min
中科院分区：
文献类型：
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作者：
Jeongsoo Kang;J. H. Hong;D. W. Hwang;J. I. Jeong;S. D. Choi;C. J. Yang;Youngnae Lee;C. G. Olson;Kicheon Kang;B. I. Min
利用光电子能谱（PES）系统地研究了RNi 2（R= Y，Ce，Pr，Nd）的电子结构，并与RCo 2的电子结构进行了比较.在R4 fPES谱中观察到双峰结构，其中E-F附近的谱权重从Ce到Pr和Nd逐渐减小，表明R4 f-Ni 3d杂化从Ce到Pr和Nd逐渐减小。对于相同的R，RNi 2中EF附近的光谱权重小于RCo 2中EF附近的光谱权重，这意味着RNi 2中与Ni 3d电子的R4 f杂化小于RCo 2中与Co 3d电子的R4 f杂化.这些趋势与RM 2（M= Co和Ni）的计算杂化矩阵元素中的趋势一致。观察到一个明显的Ni 3d卫星，这是由于Ni 3d库仑相关效应。在R Ni 2中的Ni 3d部分光谱权重分布与计算的Ni 3d角动量投影局域态密度（PLDOS）存在重要差异，如峰位和线形，表明Ni 3d关联效应显著.这些差异是定性相似，定量大于R钴2。准粒子谱密度的计算采用Hubbard哈密顿量，并包括Co和Ni的3d电子关联效应，这产生了更好的协议PES谱比局域密度近似PLDOS的。
Electronic structures of R Ni 2 (R= Y, Ce, Pr, and Nd) are investigated systematically by using photoemission spectroscopy (PES) and compared with those of R Co 2. Double-peak structures are observed in the R 4f PES spectra, in which the spectra weight near E F decreases from Ce to Pr and Nd, suggesting a decrease in the R 4f–Ni 3d hybridization from Ce to Pr and Nd. For the same R, the spectral weight near E F in R Ni 2 is smaller than that in R Co 2, implying a smaller R 4f hybridization with Ni 3d electrons in R Ni 2 than with Co 3d electrons in R Co 2. These trends are consistent with those in the calculated hybridization matrix elements for RM 2 (M= Co and Ni). A pronounced Ni 3d satellite is observed, which arises from Ni 3d Coulomb correlation effects. The Ni 3d partial spectral weight distribution in R Ni 2 exhibits important discrepancies from the calculated Ni 3d angular momentum projected local density of states (PLDOS), such as peak positions and line shapes, indicating substantial Ni 3d correlation effects. These discrepancies are qualitatively similar to, and quantitatively larger than, those for R Co 2. Quasiparticle spectral densities are calculated by using the Hubbard Hamiltonian and including Co and Ni 3d electron correlation effects, which yield a better agreement with PES spectra than the local-density approximation PLDOS’s.