Probing Strongly Correlated 4f-Orbital Symmetry of the Ground State in   Yb Compounds by Linear Dichroism in Core-Level Photoemission
  We show that the strongly correlated 4f-orbital symmetry of the ground state is revealed by linear dichroism in core-level photoemission spectra as we have discovered for YbRh2Si2 and YbCu2Si2. Theoretical analysis tells us that the linear dichroism reflects the anisotropic charge distributions resulting from crystalline electric field. We have successfully determined the ground-state 4f symmetry for both compounds from the polarization-dependent angle-resolved core-level spectra at a low temperature well below the first excitation energy. The excited-state symmetry is also probed by temperature dependence of the linear dichroism where the high measuring temperatures are of the order of the crystal-field-splitting energies. 
Takeo Mori, Satoshi Kitayama, Yuina Kanai, Sho Naimen, Hidenori   Fujiwara, Atsushi Higashiya, Kenji Tamasaku, Arata Tanaka,...
cond-mat.str-el cond-mat.mtrl-sci cond-mat.supr-con