Direct observation of the modulation of the 4f-electron orbital state by strong p-f mixing in CeSb

Low-temperature x-ray diffraction experiment has been carried out to investigate the 4 f-electron state of the low carrier density system CeSb which shows complicated magnetic phase diagrams at low temperatures. The scattering pattern of the satellite peaks observed in the magnetically ordered state AFP3 is explained well by the model which takes into account both the lattice and charge modulations corresponding to the complex magnetic structure. The present result gives direct evidence for the strong modulation of the 4 f-electron orbital state in CeSb due to the combined effect of the strong p-f mixing and carrier localization.