We report experimentally observed linear dichroism in angle-resolved core-level photoemission spectra of PrIr2Zn20 and PrB6 in cubic symmetry. The different anisotropic 4f charge distributions between the compounds due to the crystalline-electric-field splitting are responsible for the difference in the linear dichroism, which has been verified by spectral simulations with the full multiplet theory for a single-site Pr 3+ ion in cubic symmetry. The observed linear dichroism and polarization-dependent spectra in two different photoelectron directions for PrIr2Zn20 are reproduced by theoretical analysis for the Γ3 ground state, whereas those of the Pr 3d and 4d core levels indicate the Γ5 ground state for PrB6.

We have probed the crystalline electric-field ground states of pure |J = 7/2, Jz = ±5/2 as well as the anisotropic c-f hybridization in both valence fluctuating systems α-and β-YbAlB4 by linear polarization dependence of angle-resolved core level photoemission spectroscopy. Interestingly, the small but distinct difference between α-and β-YbAlB4 was found in the polar angle dependence of linear dichroism, indicating the difference in the anisotropy of c-f hybridization which may be essential to a heavy Fermi liquid state in α-YbAlB4 and a quantum critical state in β-YbAlB4 .

We present a detailed study on the 4f ground-state symmetry of the pressure-induced superconductor CeCu 2 Ge 2 probed by soft x-ray absorption and hard x-ray photoemission spectroscopy. The revised Ce 4f ground states are determined as | 7 = √ 0.45 |J z = ± 5 2 − √ 0.55 |∓ 3 2 with-type in-plane rotational symmetry. This gives an in-plane magnetic moment consistent with the antiferromagnetic moment as reported in neutron measurements. Since the in-plane symmetry is the same as that for the superconductor CeCu 2 Si 2 , we propose that the charge distribution along the c axis plays an essential role in driving the system into a superconducting phase.

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