We investigate the structures, electronic and magnetic properties of Fe \(_{x}\) Ni \(_{1-x}\) monolayer alloys deposited on the W(110) surface (i.e., Fe \(_{x}\) Ni \(_{1-x}\) /W(110)), using the density functional theory (DFT) calculations, including the effect of Hubbard correction U, i.e., DFT+U. Various combinations of ferromagnetic (FM) and ferrimagnetic (FI) orientations, including non-magnetic (NM) configurations of Fe \(_{x}\) Ni \(_{1-x}\) (x varies from 0 to 1), are considered. Our calculations show that most energetically favourable configurations for the Fe-Ni alloys on the W(110) surface are when the concentration x of Ni is greater than that of Fe and where the Fe and Ni have exhibited a ferrimagnetic coupling. Also, crystal orbital Hamilton population (COHP) reveals the absence of antibonding states around the +1 eV near the Fermi energy in the case of the ground-state FI configurations and the existence of such antibonding states at the same energy level in the case of NM configurations, as the possible origin of preferred stability of the FI configuration (i.e., relative to NM). Furthermore, a comparison between the magnetization in free-standing Fe \(_{x}\) Ni \(_{1-x}\) and that of Fe \(_{x}\) Ni \(_{1-x}\) /W(110) systems show that the W(110) substrate acts to reduce the magnetic moment of alloy atoms of Fe and Ni. This can be adduced to electron transfer between the orbitals of Fe, Ni and W atoms. Interestingly, such an electron transfer also enhances the stability of the alloys on the W(110) substrate. Our work provides deeper understanding of atomic-scale properties of Fe-Ni alloys deposited on a W(110) substrate which can be useful to understand similar epitaxial layers.
