Effect of Substrate on Structural and Electronic Properties of Au-Pd, Au-Pt and Au-Ag Atomic Chains

We report structure and electronic properties of Au-Pd, Au-Pt and Au-Ag bimetallic atomic chains absorbed on NiAl(110) and Cu(110) substrate. It is found that the presence of substrate significantly influences the electronic structure of the chains. Atoms of single chains of Au-Pd, Au-Pt and Au-Ag bind more strongly with Ni atoms of NiAl substrate, as compared with Cu atoms in Cu(110). The interaction between chain atoms is found stronger than the chain-substrate atoms, when chains are placed on Cu substrate, while it is other way round in case of chains on NiAl substrate. Effect of change in positions of atoms in bimetallic chains in presence of substrate is studied by placing double chains of Au-Pd, Au-Pt and Au-Ag on Cu (110) substrate in three different configurations. It is found that Au-Pd and Au-Pt bimetallic chains stabilize in double zigzag topology, when placed on Cu (110) substrate. While Au-Ag chains exhibit ladder topology on Cu(110) substrate. Ferromagnetism that is observed in ground state of free standing chains of Au-Pd and Au-Pt is not found when chains are absorbed on NiAl(110) and Cu(110) substrate. It is likely that the interaction between chain and substrate atoms results to zero magnetic moment.