First principles theory of artificial metal chains on NiAl(110) surface

Abstract

Using first-principle calculations we have studied the stable phases of metal-atom chains on the ͑110͒ surface of NiAl. Our investigation is mainly focused on the technologically relevant case of Au chains, but the results will be analyzed in the broader framework of a family of metallic systems. We demonstrate that the nature of the adatom ͑Au, Mn, Ni, Cu, Al, H, C, Na, K, and Ca͒ is responsible for different levels of interaction with the substrate and gives rise to a variety of electronic behaviors. With some transition metals ͑such as Au, Mn, Ni, and Cu͒ the NiAl surface acts as a simple structural template for the formation of the artificial one-dimensional system and does not affect the electronic properties of the chains. With other atomic species ͑H, C, Na, K, and Ca͒ we observe substantially different couplings and stronger interactions. We demonstrate that the different electronic properties of the various adatoms are responsible for different couplings with the substrate and compare our findings with the existing experimental results. Finally, in the case of Au chains we have investigated the role of adatom-adatom interactions in the formation of such one-dimensional structures.

Magnetic order and exchange interactions in monoatomic3dtransition-metal chains

“…33 A subsequent theoretical study confirmed the weak perturbation of the electronic structure also for Mn chains. 34 We demonstrate here that the effect on the magnetic properties of monoatomic chains can be dramatic. For example, Cr and Mn chains show weak antiferromagnetic coupling while for Fe and Co the FM and AFM solution are degenerate within 2 meV per chain atom, suggesting the possibility of a more complex, noncollinear ground state due to higher-order spin interactions.…”

“…In this geometry every chain atom possesses two chain atoms as well as five surface atoms as nearest neighbors. In a previous theoretical study 34 it has been demonstrated that the electronic properties of Mn, Ni, Au, and Cu chains are only weakly perturbed in this configuration on NiAl͑110͒; however, the magnetic order was not considered. The interatomic distance in the chains is dictated by the substrate lattice constant.…”

First‐principle studies of dissociative adsorption of H2O on NiAl(110)‐(2 × 2) surface

“…This adsorption energy is also in agreement with the other theoretically calculated value of −3.60 eV by Calzolari and Nardelli. [16] In initial structures for all sites, the molecular plane of H 2 O was parallel to the surface and the symmetry axis of H 2 O was parallel to [001]. The lowest energy structures from the initial guesses for each of the sites are shown in Fig.…”

Optical Generation of Collective Plasmon Modes in Small Gold Chains Induced by Doping Transition-Metal Impurities

“…Calculations of optimized Au-Au bond lengths show that the optical absorption spectrum does not depend significantly on the interatomic distance d in the range 2.5Å (optimized bond length for the chains) and 2.89Å (the experimental interatomic distance corresponding to Au chains on NiAl(110) substrate [6]). We have set the Au-Au distance as the latter to mimic the experimental setup, while cognizant of the fact that even though NiAl(110) surface does not affect the electronic properties of the Au chains [18], it can have strong implications for its optical properties. For doped chains, we optimized the bond lengths in the Au-X dimer and Au-X-Au trimer.…”