Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 25: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles II (jointly with TT)
O 25.2: Vortrag
Dienstag, 27. März 2012, 11:00–11:15, HE 101
Dynamical screening of the large local magnetic moment in Fe-based superconductors — •Alessandro Toschi1, Ryotaro Arita2, Philipp Hansmann1,3, Shiro Sakai1,3, Giorgio Sangiovanni1, and Karsten Held1 — 1Institute of Solid State Physics, Vienna University of Technology (Austria) — 2Department of Applied Physics, University of Tokyo (Japan) — 3Ècole Polytechnique, Palaiseau Cedex (France)
Electronic correlation plays a subtle role in Fe-based superconductors. In fact, due to the presence of several moderately correlated bands close to the Fermi level, one observes the formation of a large local magnetic moment driven by the Hund’s exchange interaction, which takes place, however, in a mainly metallic background ("Hund’s metal"[1]). This physical scenario, as it is shown by our LDA+DMFT calculations[2,3], provides the key to understand the discrepancies observed between experimental estimates of the magnetic moment in the magnetically ordered phase and those obtained via standard LSDA calculations. The magnitude of the discrepancy observed in different compounds would be hence related to the efficacy of the metallic screening, which is decreasing when going from the 1111 (e.g., LaFeAsO) to the 122 class, and eventually to the 11 materials (e.g., FeTe).
[1] K. Haule and G. Kotliar, New J. Phys. 11, 025021 (2009).
[2] P. Hansmann, R. Arita, A. Toschi, S. Sakai, G. Sangiovanni, and K. Held, Phys. Rev. Lett. 104, 197002 (2010).
[3] A. Toschi, R. Arita, P. Hansmann, G. Sangiovanni, and K. Held, in preparation.