arXiv subjects

L. Szunyogh

Publications and source records attributed to L. Szunyogh.

57 records · Page 4Linked to original sources

arXiv2000

A First-Principles Theory of Bloch Walls in Ferromagnets

We present a first principles account of Bloch Walls on the basis of relativistic Spin-Density Functional Theory in the Local Density Approximation (LDA). We argue that calculations based on this description will provide useful and novel informations about the physics of this important element of micro-magnetics. To illustrate the points we wish to make we implement the proposed calculations for Fe and determine the Bloch Wall thickness $\ell_{BW}$. Moreover we study features of the electronic structure which arise due to the presence of the Bloch Wall.

cond-mat.mtrl-sci↗

arXiv2000

Theory of the Fano Resonance in the STM Tunneling Density of States due to a Single Kondo Impurity

The conduction electron density of states nearby single magnetic impurities, as measured recently by scanning tunneling microscopy (STM), is calculated, taking into account tunneling into conduction electron states only. The Kondo effect induces a narrow Fano resonance in the conduction electron density of states, while scattering off the d-level generates a weakly energy dependent Friedel oscillation. The line shape varies with the distance between STM tip and impurity, in qualitative agreement with experiments, but is very sensitive to details of the band structure. For a Co impurity the experimentally observed width and shift of the Kondo resonance are in accordance with those obtained from a combination of band structure and strongly correlated calculations.

cond-mat.str-el↗

arXiv2000

A proper ballistic calculation of tunneling conductance for real junctions

Employing an ab initio Screened Korringa-Kohn-Rostoker (SKKR) band structure method for a metal-vacuum-metal junction, we find that the tunnel conductance is different when it is calculated across the barrier and far from it. We attribute this difference to an artefact of the ballistic approach which overestimates the role of specular reflections, and its inability to pick up contributions from localized interface states. To reconcile the ballistic approach with experiment, we propose that the tunnel conductance should be calculated as if it is measured directly across the barrier. In this case the predicted tunneling magnetoresistance is larger.

cond-mat.mes-hall↗