Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Surface and Interface Magnetism I (O jointly with MA)
O 51.2: Vortrag
Mittwoch, 2. April 2014, 10:45–11:00, WIL C107
Controllable Kondo Effect of Fe on Alkali Substrates — •Malte Schüler1,2, Tim O. Wehling1,2, Sandra Gardonio3, and Carlo Carbone4 — 1Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany — 2Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany — 3Materials Research Laboratory, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia — 4Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Basovizza, I-34149 Trieste, Italy
The interaction between a magnetic impurity and a non-interacting bath presents a characteristic case of a multiorbital Kondo system. Prototypical realizations are Fe adatoms on alkali-surfaces (in our case Li, Na, K, Cs). The different substrates lead to different hybridization strengths, caused by the decrease of electron density with the increase of the lattice constant.
The electronic configuration and the magnetization of the impurity are measured by XMCD and XAS. Multiplet-broadening and a decrease of magnetic moment with increasing electronic density are observed. The simulation of this behavior leads to understanding how orbital degree of freedom influences the Kondo effect: The orbital resolved hybridization is obtained by fully relaxed DFT calculations and is used as a starting point to model the impurity problem with different complexity. These models are solved by numerical renormalization group, exact diagonalization and quantum Monte Carlo methods and compared to the experimental data.