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arXiv · 1501.02584

Electron-electron interaction strength in ferromagnetic nickel determined by spin-polarized positron annihilation

Hubert Ceeh·Josef-Andreas Weber·Peter Böni·Michael Leitner·Diana Benea·Liviu Chioncel·Dieter Vollhardt·Hubert Ebert·Jan Minar·Christoph Hugenschmidt
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Abstract

The two-photon momentum distribution of annihilating electron-positron pairs in ferromagnetic nickel (Ni) was determined by measuring the spin-polarized two-dimensional angular correlation of annihilation radiation (ACAR). The spectra were compared with theoretical results obtained within LDA+DMFT, a combination of the local density approximation (LDA) and the many-body dynamical mean-field theory (DMFT). The self-energy describing the electronic correlations in Ni is found to make important anisotropic contributions to the momentum distribution which are not present in LDA. Based on a detailed comparison of the theoretical and experimental results the strength of the local electronic interaction U in ferromagnetic Ni is determined as 2.0 +- 0.1 eV.

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Hubert Ceeh, Josef-Andreas Weber, Peter Böni, Michael Leitner, Diana Benea, Liviu Chioncel, Dieter Vollhardt, Hubert Ebert, Jan Minar, Christoph Hugenschmidt. 2015-01-12. Electron-electron interaction strength in ferromagnetic nickel determined by spin-polarized positron annihilation. https://doi.org/10.1038/srep20898

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