TiNi Monatomic Chains Stabilized by Alloying: a First-Principles Study

Total energies and electronic structures calculations are performed for the monatomic TiNi alloy chains with the linear and zigzag structures. The pure Ti and pure Ni atomic chains have also been computed on equal footing, serving as reference systems. The results shows that the stability of one-dimensional chains can be enhanced by alloying, i.e. the cohesive energies of TiNi alloy chains are larger than the corresponding pure Ti and Ni ones, in both the linear and zigzag structures. The stability effect by alloying is associated with changes of the electronic properties, such as the lowering of the density of states at the Fermi level and more covalently bonding between the Ti and Ni sites. Compared to the zigzag TiNi chain, the stability of linear TiNi chains has been more increased.