Structural, electronic, and magnetic properties of clean and Ag-covered Fe monolayers on W(110)

The structural, electronic, and magnetic properties of magnetic Fe transition-metal atoms as an overlayer on a nonmagnetic transition metal, W(110), and the effects of a Ag covering on the magnetism of Fe/W(110), are determined by means of the highly precise self-consistent all-electron full-potential linearized-augmented-plane-wave method based on the local-spin-density approximation. The interlayer spacings of Fe-W and Ag-Fe are determined from total-energy calculations. We find that the Fe atoms are relaxed downward (compared to the average of the Fe-Fe and W-W bulk bond lengths) by 9.5% and 4.0% for clean and Ag-covered Fe/W(110), respectively. We find that the hybridization of the W and Fe d bands plays an important role in determining the magnetism of the Fe/W(110) systems. The magnetic moment (2.18B) and the magnitude of the Fermi-contact hyperfine field (-148 kG) of the Fe in relaxed Fe/W(110) are greatly reduced compared to those of the unrelaxed Fe/W(110) (by 0.38B and 46 kG, respectively). The Ag covering increases the magnitude of the Fermi-contact term of the Fe by 29 kG by encouraging the indirect covalent spin polarization of the s-like electrons. If one includes estimates of the dipolar and unquenched orbital-angular-momentum contributions, then our calculated values of the hyperfine field are found to be in remarkable agreement with recent conversion-electron Mössbauer-spectroscopy experimental values.