Chemical bonding states at copper/graphite interfaces with additional elements

Chemical bonding states of Cu/graphite interfaces were investigated by using the first-principles molecular orbital method with model clusters. It was found that Cu atoms in the interface layer undergo electronic overlap with C atoms at the first and second neighboring sites. Chemical bonding strength across the interface is strongly affected by the presence of Ti or Zr in the interface layer. The interfacial attractive interaction increases by doping the larger-sized Ti or Zr atom, although the interlayer distances between Cu and graphite become larger. Therefore, the interface strength of Cu/graphite can be improved by the additional elements at the interface.