Magnetism of Co nanoparticles supported on the Cu(111) substrate: Size and environment dependence

We report a tight-binding calculation of the magnetic properties of triangular Co nanoparticles with two monolayers height supported on the (111) substrate of Cu. This system has been recently characterized through scanning tunneling microscopy measurements. The spin-polarized electronic structure is self-consistently determined by solving a tight-binding Hamiltonian for the 3d, 4s, and 4p valence electrons. Different particle sizes as well as different particle concentrations over the surface are considered in order to investigate the influence of the local environment on the magnetic map of the system. The resulting trends are discussed by comparing with those obtained from available measurements for free-standing Co clusters, and with the asymptotic limit of a Co bilayer on Cu(111).