Structure and stability of ultrathin Fe films on W(110)

Abstract

The growth of one and two atomic layers of iron on a W(110) substrate was followed by low-energy electron microscopy. The near-surface structural properties of the perfectly flat pseudomorphic films were studied by quantitative low-energy electron diffraction analysis from areas of uniform thickness as well as by the density functional theory. A strong relaxation of the outermost atomic layers was found in Fe mono-and bi-layers on W(110). By calculating the phonon dispersion relations and phonon density of states, the stability of the pseudomorphic iron bi-layer on a tungsten substrate has been addressed. To complete the physical picture, an iron tri-layer has also been analysed in order to identify the source of instability for its pseudomorphic phase. Our results show that the surface instability originates from the softening of the in-plane surface modes along the [1-10] direction, although the soft modes were not observed. The enhanced magnetic moments calculated within the density functional theory are in good agreement with experimental findings reported for these systems.

Structural and electronic properties of Fe monolayer on BaTiO3(0 0 1)

“…Information about both types of the deformations can be obtained from the lattice dynamics studies, which to the best of our knowledge have not been yet reported for the Fe/BaTiO 3 interface neither for the clean BaTiO 3 surface. Since the significant changes in vibrational properties were observed in other nanosystems such as the Fe/W(1 1 0) [26][27][28], FeO/Pt(1 1 1) [29], and EuSi 2 /Si(0 0 1) thin films [30], similar effects can be expected in the Fe/BaTiO 3 interface.…”

Spin reorientation transition in an ultrathin Fe film on W(110) induced by Dzyaloshinsky-Moriya interactions

“…The bulk lattice constant of bcc Fe is a Fe = 2.867 Å, and of bcc W is a W = 3.165 Å. Due to this large lattice mismatch, there is a considerable inward relaxation of the Fe layers, which has been confirmed by experimental [30][31][32] as well as theoretical [33][34][35] investigations. In our calculations the distance between the top W layer and the interfacial Fe layer was chosen to be 2.01 Å, while the distance between the interfacial and surface Fe layers was set to 1.71 Å, according to the results of earlier studies based on density functional theory calculations [34,35].…”

Metadynamics study of the temperature dependence of magnetic anisotropy and spin-reorientation transitions in ultrathin films

“…Since a DL of Fe grows pseudomorphically on W(110) [50], two-dimensional translational symmetry is applied throughout the whole system with the lattice constant of bcc bulk W (a W = 3.16 Å). According experimental [51] and theoretical [52] studies there is a considerable inward relaxation of the Fe layers due to the large lattice mismatch between Fe and W. Following Ref. 53, the Fe-W and Fe-Fe layer distances were chosen as 2.01 Å and 1.71 Å, respectively.…”