6533b7d8fe1ef96bd1269827
RESEARCH PRODUCT
Energy- and angle-dependent threshold photoemission magnetic circular dichroism from an ultrathin Co/Pt(111) film
Toshihiko YokoyamaGerd SchönhenseKartick TarafderTakeshi NakagawaPeter M. OppeneerHans-joachim ElmersK. Hildsubject
PhysicsCondensed Matter::Materials ScienceMagnetic circular dichroismAngle of incidence (optics)Ab initio quantum chemistry methodsInverse photoemission spectroscopyAngle-resolved photoemission spectroscopyFresnel equationsPhoton energyAtomic physicsCondensed Matter PhysicsExcitationElectronic Optical and Magnetic Materialsdescription
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 (Gamma-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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-11-15 | Physical Review B |