Electronic transport in iron atomic contacts: from the infinite wire to realistic geometries

Abstract

We present a theoretical study of spin polarized transport in Fe atomic contacts using a self-consistent tight-binding Hamiltonian in a non-orthogonal $s$, $p$ and $d$ basis set, the spin-polarization being obtained from a non-collinear Stoner-like model and the transmission probability from the Fisher-Lee formula. The behaviour of an infinite perfect Fe wire is compared with that of an infinite chain presenting geometric defects or magnetic walls and with that of a finite chain connected to infinite one-dimensional or three-dimensional leads. In the presence of defects or contacts the transmission probability of $d$ electrons is much more affected than that of $s$ electrons, in particular, contact effects may suppress some transmission channels. It is shown that the behaviour of an infinite wire is never obtained even in the limit of long chains connected to electrodes. The introduction of the spin-orbit coupling term in the Hamiltonian enables us to calculate the anisotropy of the magneto-resistance. Finally whereas the variation of the magneto-resistance as a function of the magnetization direction is step-like for an infinite wire, it becomes smooth in the presence of defects or contacts.

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• Anisotropic magnetoresistance: materials, models and applications
• Symmetry aspects of spin-filtering in molecular junctions: hybridization and quantum interference effects
• Shot noise and magnetism of Pt atomic chains: accumulation of points at the boundary
• Quenching of magnetic excitations in single adsorbates at surfaces: Mn on CuN/Cu(100)
• Impact of dimerization and stretching on the transport properties of molybdenum atomic wires
• Defect engineering of the electronic transport through cuprous oxide interlayers
• Giant anisotropic magnetoresistance through a tilted molecular $\pi$-orbital
• Comparative study of tight-binding and ab initio electronic structure calculations focused on magnetic anisotropy in ordered CoPt alloy
• Electronic transport calculations for rough interfaces in Al, Cu, Ag, and Au
• Spin-polarized currents generated by magnetic Fe atomic chains