Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 5: Rastersondentechniken I

O 5.3: Vortrag

Montag, 24. März 2003, 11:45–12:00, FOE/ORG

Tunnel magneto-resistance in spin-polarized scanning tunneling spectroscopy calculated within scattering theory — •Piotr Karaś, Jürgen Henk, and Patrick Bruno — Max-Planck-Institut für Mikrostrukturphysik, Halle (Saale)

The interpretation of scanning tunneling spectroscopy (STS) is usually based on the Tersoff-Hamann (TH) model which, however, neglects important features of the tunneling process. To go beyond the TH model, we have formulated spin-polarized STS in terms of scattering theory.

Besides a presentation of the general formalism and its implementation in our spin-polarized relativistic layer-KKR computer code, we focus in this contribution on the magneto-resistance in spin-dependent tunneling between a ferromagnetic sample and a ferromagnetic STM tip. The magneto-resistance depends unequivocally on the energy-dependent spin-resolved electronic structure of the tip, thus, revealing limitations of the TH model.