Growth and magnetism of one Mn monolayer on Ag(100)

Abstract

Structural properties of Mn films, with a thickness of one monolayer (ML), deposited on a Ag(100) substrate have been investigated both experimentally (photoemission and ion scattering spectroscopies) and theoretically (tight-binding linear muffin-tin orbital method). The magnetic structure of the films and the effect of magnetism on their relative stability have been investigated ab initio. We find that after Mn evaporation [at room temperature (RT)], a superficial MnAg alloy is formed. Mild annealing gives rise to the formation of an (almost) inverted Mn monolayer covered by a Ag plane, i.e., the second atomic plane of the sample is mainly constituted by Mn atoms, whereas the first atomic layer is almost a pure Ag plane. A complete inversion of the Mn ML can be obtained by direct sequential deposition of Mn and Ag at 80 K. Our calculations on the energetic stability of 1 ML of Mn on top of Ag(100) versus 1 ML of Mn covered by one Ag atomic plane, show that the second situation is energetically preferred. This is also true when this situation is compared to the formation of a 2-ML-thick MnAg alloy on Ag(100). We find that the inverted Mn monolayer tends to be ferromagnetic and that magnetism acts against interdiffusion.