First-principles study on the improvement of Cu/EP interfacial properties by Ti, Cr, and rare-earth elements (La Y Ce)

In this work, first-principles calculations based on density functional theory (DFT) were employed to systematically investigate the regulation mechanisms of Ti, Cr, and rare-earth elements (La, Y, Ce) doping on the interfacial bonding properties of Cu/EP composites. By calculating the interfacial energy, density of states, and charge density difference, the evolution of interfacial electronic structures under different doping elements, doping concentrations, and bilayer configurations was compared and analyzed. The results show that Ce doping significantly enhances the interfacial energy through direct hybridization between Ce-f and Cu-p orbitals, forming CeCu metallic bonds. The interfacial strengthening effects of Ti and Cr increase with doping concentration. Moreover, the Ti/Cu bilayer structure exhibits the lowest interfacial energy, representing the optimal interfacial modification layer. Analysis of the density of states reveals that after doping with Ti, Cr, and rare-earth Ce, the Cu-p orbital density of states in the energy range from -10eV to 20eV exhibits varying degrees of sharpening, indicating a transition from physical adsorption to chemical bonding at the interface. This study elucidates the interfacial bonding behavior and regulation mechanisms of different modifying elements, providing a theoretical basis for the modification design and practical application of high-performance Cu/EP composite interfaces.