Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
J Phys Condens Matter. 2011 Dec 14;23(49):495601. doi: 10.1088/0953-8984/23/49/495601. Epub 2011 Nov 17.
Employing high resolution photoemission spectroscopy, we studied the evolution of the spectral features in rare earth hexaboride single crystals as a function of temperature and 4f binding energy, where the variation of the 4f binding energy is obtained by changing the rare earth element. High energy resolution helped to reveal the distinct features corresponding to the various photoemission final states. Experimental results of CeB(6), a dense Kondo system, exhibit the growth of the features near the Fermi level with the decrease in temperature relative to the uncompensated local moment contributions. The valence band spectra of the antiferromagnetic compounds, PrB(6) and NdB(6), exhibit multiple features-the 4f ionization peaks (poorly screened features) appear at higher binding energies and the features in the vicinity of the Fermi level possessing significant 4f character are due to the well-screened photoemission final states. These results indicate finite hybridization between the 4f and B 2s2p conduction electronic states. Interestingly, the well-screened features in PrB(6) and NdB(6) exhibit unusual enhancement in intensity at low temperature.
采用高分辨率光电子能谱，我们研究了作为温度和 4f 结合能函数的稀土六硼化物单晶的光谱特征的演化，其中 4f 结合能的变化是通过改变稀土元素获得的。高能分辨率有助于揭示对应于各种光电子发射终态的不同特征。密近藤系统 CeB(6)的实验结果表明，与未补偿局部磁矩贡献相比，在温度降低时，费米能级附近的特征增加。反铁磁化合物 PrB(6)和 NdB(6)的价带光谱表现出多个特征 - 4f 离子化峰（屏蔽不良的特征）出现在较高的结合能处，而费米能级附近具有显著 4f 特征的特征归因于良好屏蔽的光电子发射终态。这些结果表明 4f 和 B 2s2p 传导电子态之间存在有限的杂化。有趣的是，PrB(6)和 NdB(6)中的屏蔽良好的特征在低温下表现出异常增强的强度。
