High-resolution angle-resolved photoemission study of electronic structure near the Fermi level in strongly correlated f-electron materials

我们在使用一种新的微波刺激放电灯的情况下成功地实现了能量分辨率比5 MeV好。有了这个光发射光谱仪，我们已经研究了几种与f-或d-电子相关的材料，并找到了后续的新发现。我们在直接观察到费米表面拓扑结构中的变化与CeSb中的磁性相位转换一起成功了。我们发现，过渡中的驱动力是异源p-f混合物。我们第一次在CeRhAs和CeRhSb中发现了一个温度相关的小假隙。我们已经将假间隙转化为Kondo绝缘体间隙通过f-d杂交形成。We have mapped out the“？structure”of the heavy-fermion superconductors Upt_D23__通过与波段计算进行比较，我们发现p和d轨道的Valence-波段结构一致性的主要主体显示了实验之间的良好协议，而计算时，在波段附近的波段在E-D-2中产生了明显的狭窄，可能与强电子相关。We have mapped out the“\structure”of USb and Compared with CeSb。我们发现USB是一种金属，它与费米表面形成了一种与半金属CeSb形成对比的U6 d和U 5 f电子。我们已经将其归因于4F和5 F水平的能量位置的差异。We found a pseudogap in Bi2212 high-T型D2c型D2 superconductors， which opens at E型D2F型D2 above the superconducting transition temperature （T型D2c型D2） for various hole concentrations from under to optimal doping。我们发现了两个具有不同能量尺度和温度依赖性的不同伪粒;一个是超导电间隙的预cursor和反磁相关中的其他起源。我们已经确定了Bi 2212的精确费米表面，并在X点确认了它的空洞拓扑。

We have succeeded in performing an energy resolution better than 5 meV by using a new micro-wave excited discharge lamp. With this photoemission spectrometer, we have studied several f- or d-electron correlated materials and obtained the following new findings.1. We have succeeded in directly observing the change in the Fermi surface topology accompanied with the magnetic phase transition in CeSb. We found that the driving force in the transition is the anisotropic p-f mixing.2. We found for the first time a temperature dependent small pseudogap at the Fermi level in CeRhAs and CeRhSb. We have ascribed the pseudogap to the Kondo insulator gap formed through the f-d hybridization.3. We have mapped out the "band structure" of the heavy-fermion superconductors UPtィイD23ィエD2 and URuィイD22ィエD2SiィイD22ィエD2. By comparing with the band calculations, we found that the main body of the valence-band structure consisting of p and d orbitals shows a good agreement between the experiment and the calculation while the bands near EィイD2FィエD2 originating in the f orbital are remarkable narrower in the experiment, probably due to the strong electron correlation.4. We have mapped out the "band structure" of USb and compared with CeSb. We found that USb is a metal with Fermi surfaces consisting of U6d and U5f electrons in contrast with semimetallic CeSb. We have ascribed this to the difference in the energy position of 4f and 5f levels.5. We found a pseudogap in Bi2212 high-TィイD2cィエD2 superconductors, which opens at EィイD2FィエD2 above the superconducting transition temperature (TィイD2cィエD2) for various hole concentrations from under to optimal doping. We found two different pseudogaps with different energy scale and temperature dependence ; one is a precursor of the superconducting gap and the other originates in the antiferromagnetic correlation.6. We have determined the precise Fermi surface of Bi2212 and confirmed its hole-like topology centered at X point.