Role of pressure induced c-f hybridization on the valence transition in EuPd₂Si₂

Tetragonal EuPd₂Si₂ is well-known to show a valence transition from divalent (Eu²⁺) to trivalent (Eu³⁺) states by a change in temperature or pressure. However, its mechanism has not been completely studied yet. In this presentation, we will address the microscopic origin of the valence transition in tetragonal EuPd₂Si₂ under pressure using a combination of ab initio calculations and photoemission measurements. Our results indicate that an enhanced c-f hybridization between localized Eu 4f states and itinerant conduction states ( Eu 5d, Pd 4d, and Si 3p ) plays a vital role for the valence transition to happen. Lastly, the effects of Au doping on the valence states of EuPd₂Si₂ will be also discussed.