Interface bonding and mechanical properties of copper/graphene interface doped with rare earth elements: First principles calculations

The interface doping with rare earth elements is a novel strategy to enhance the weak interface bonding of copper-graphene system (Cu-G). In this work, taking Sc, Y, La as representatives, we investigated the structural, electronic and mechanical properties of clean and doped Cu-G systems using first principles calculations. By the comparison of interface spacing and work of separation with clean system, the significantly improved interface interaction in rare earth elements doped systems has been verified. Besides, difference charge density, Bader charge and density of states were employed to reveal the microscopic modifying mechanism on the atomic scale. Then, the tensile stress-strain curves were obtained using a fitting function related with the element electronegativity, and thus the quantitative relationship between the interface bonding and mechanical properties was determined, which could provide theoretical guidance for the interface modification of Cu-G composites through doping rare earth elements.