Phase transition of nanoscale Au atom chains on NiAl(110)

Abstract

Recently, 1D Au single atom chains (SAC) were artificially constructed on the NiAl(110) surface in experiment, which has stimulated various experimental and theoretical investigations on its potential applications such as in microelectronics and catalysis. Here, we reexamine their relative stabilities and formation mechanism on NiAl(110) using first-principles calculations. We reveal that in the range of N = 2 similar to 6, the formation of SAC is energetically more stable than that of 1D Au bi-atom chains (BAC), mainly due to the electronic quantum confinement effects. However, beyond N = 6, BAC are found to be energetically favored over SAC due to the energy gain of Au-Au bonding. The present findings reveal the importance of the competition between electronic quantum confinement, the adatom-adatom interactions, and adatom-substrate interactions in formation of the desirable 1D nanostructures. (C) 2019 Elsevier B.V. All rights reserved.