Dresden 2014 – scientific programme

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MI: Fachverband Mikrosonden

MI 2: Untersuchung von kondensierter Materie mittels Positronen-Annihilation

MI 2.4: Talk

Monday, March 31, 2014, 11:15–11:30, MER 02

Spin polarized 2D-ACAR study of the electronic structure of Nickel — •Hubert Ceeh¹, Josef-Andreas Weber¹, Michael Leitner¹, Christoph Hugenschmidt¹, Liviu Chioncel², Diana Benea³, and Peter Böni¹ — ¹Technische Universität München, Physik Department, Lehrstuhl E21, James-Franck-Straße, D-85748 Garching, Germany — ²Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany — ³Chemistry Department, University Munich, Butenandstraße 5-13, D-81377 München, Germany

2D-ACAR (Angular Correlation of Positron Annihilation Radiation) is a well known technique for the investigation of the electronic structure, i.e the Fermi surface of a material. For the properties of a metal the Fermi surface is a most important characteristic as it defines the boundary between occupied and unoccupied states in reciprocal space. In this contribution we give an overview on the measurement principle of spin-polarized 2D-ACAR. We then present our measurement of the momentum-density distributions of magnetic electrons in Nickel and compare these results with recent theoretical calculations based on the combined density functional and dynamical mean field theory. The overall structure of the experimental momentum densities are already reasonably reproduced without including dynamical electronic correlations, however we show that the slight quantitative discrepancies are reduced including the electronic correlations.