STRUCTURAL AND MAGNETIC-PROPERTIES OF TETRAGONALLY DISTORTED IRON

Thin films grown on a substrate hardly ever have a perfect cubic symmetry due to a mismatch in lattice constant between the film and the substrate. If the films are thicker than a few monolayers it is possible to compare their electronic structure with that of a bulk material in a distorted geometry. We have calculated the electronic structure and total energy of tetragonally distorted iron in order to compare with experiments performed on fcc-like iron films grown on Cu(100). Our calculations are consistent with the observed structural and magnetic properties of such films. Our total energy results are also helpful in understanding which types of films will grow on a particular substrate and how many monolayers one can expect to grow before the structure of the iron film relaxes to the equilibrium bcc structure.