Temperature-Induced Valence Transition of EuPd₂Si₂Studied by Hard X-ray Photoelectron Spectroscopy

Abstract

We have studied the electronic structure of EuPd2Si2 by hard X-ray photoelectron spectroscopy (HX-PES) from 300 to 20 K. The temperature-dependent HX-PES spectra clearly show the valence transition, namely, the intensities of the divalent and trivalent Eu 3d components are abruptly changed. The change in Eu 3d spectral shape, especially the drastic change in the trivalent Eu 3d feature with temperature, can be explained within the framework of the Anderson model. The peak shift of Pd 3d core level with temperature indicates that the valence electrons of Pd contribute to the temperature-induced valence transition of EuPd2Si2.