Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: Electronic structure of surfaces: Spectroscopy, surface states I
O 32.4: Vortrag
Dienstag, 13. März 2018, 14:45–15:00, MA 004
Layer thickness dependence of the Kondo temperature in the surface alloy CePt5 on Pt(111) — •Katharina Treiber, Philipp Eirich, Chul Hee Min, and Friedrich Reinert — Experimentelle Physik VII, Universität Würzburg
At low temperatures local interactions between Ce 4f-and conduction electrons in thin films of CePt5 on Pt(111) lead to a spectral feature at the Fermi surface - the Kondo resonance [1]. This inelastic scattering process leads to a reduction of the f-level occupancy to nf < 1. This is reflected in the Ce 3d core levels. The spectral weight of their spin orbit split 3d 3/2- and 5/2 peaks is redistributed on six peaks mirroring the f-level occupation [2]. Previous studies have shown that the CePt5 surface alloy appears in a variety of different phases depending on Ce coverage and post annealing procedure [3]. XAS and XMCD studies recently suggested a change of the correlation strength throughout those different phases [4].
In this contribution we examine the electronic structure of the different phases regarding their various structural changes, by XPS and ARPES. We explore the hybridization strength and effective occupancy of the 4f-electrons as a function of temperature, probing depth and CePt5 layer thickness. This provides us with an opportunity to tune the strength of the electronic correlation in CePt5 on Pt(111). [1] M. Garnier et al., Phys. Rev. B 56, R11399(R), (1997) [2] O.Gunnarsson, K. Schönhammer, Phys. Rev. B 28, 8, (1983) [3] J. Kemmer et al., Phys. Rev. B 90, 195401 (2014) [4] C. Praetorius et al., Phys. Rev. B 92, 045116, (2015)