Energy- and angle-dependent threshold photoemission magnetic circular dichroism from an ultrathin Co/Pt(111) film

K. Hild, G. Schönhense, H. J. Elmers, T. Nakagawa, T. Yokoyama, K. Tarafder, P. M. Oppeneer

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6 Citations (Scopus)

Abstract

Threshold photoemission magnetic circular dichroism (TPMCD) in one-photon photoemission (1PPE) and two-photon photoemission (2PPE) is measured at an ultrathin Co film grown on Pt(111). Energy-dependent measurements reveal maximum asymmetries directly at the photoemission threshold (1.90% for 1PPE and 11.7% for 2PPE) which weakly decrease with increasing photon energy. The measured TPMCD asymmetries are discussed in two excitation models on the basis of spin-resolved band-structure calculations. For the model of direct band-to-band transitions in other k directions than the direction of observation (Γ-L) ab initio calculations for 1PPE and 2PPE are performed. The theory is in reasonable agreement with the measured TPMCD responses. An explanation of the large 2PPE TPMCD signal is provided in terms of specific interband excitations within the first excitation step. In the case of 2PPE angle-dependent measurements reveal a continuous drop of the asymmetry with increasing angle of incidence that agrees perfectly well with a calculation using the Fresnel equations. For 1PPE a deviation from the Fresnel-field approximation is obvious.

Original languageEnglish
Article number195430
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume82
Issue number19
DOIs
Publication statusPublished - Nov 15 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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