Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 5: Electron Theory of Magnetism
MA 5.4: Vortrag
Montag, 23. März 2009, 11:45–12:00, HSZ 103
Local correlation effects in Co2Mn1−xFexSi Heusler alloys — •Stanislav Chadov1, Gerhard H. Fecher1, Claudia Felser1, Jan Minár2, Jürgen Braun2, and Hubert Ebert2 — 1Johannes Gutenberg University Mainz, Germany — 2Ludwig Maximillians University Munich, Germany
Strongly correlated electron systems possess an important entry among the Heusler materials. Of the special technological interest are Co2Mn1−xFexSi alloys which being highly spin-polarized systems exhibit the highest known magnetic moments ranging from 5 to 6 µB and the Curie temperatures from 985 to 1100 K. Former theoretical studies evidence the local correlation as an important mechanism responsible for their extreme magnetic properties. We analyze this mechanism by studying the electronic structure with ab-initio calculations combining the well-known LSDA approach and the state of the art many-body DMFT scheme. The approach is implemented within the KKR Green’s function method. We find both static and dynamic local correlations as an essential ingredient in a description of the electronic structure. Results obtained for the magnetic moments and the photoemission spectra are much improved comparing to the plain LSDA and found to be in a good agreement with experiment. In addition we also discuss the correspondence between the physical properties and the certain types of the many-body interaction.
The authors gratefully acknowledge financial support by the DfG (Research Unit 559).