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Interplay of Magnetism and Bonding in Spin-Ladder Iron Selenides

Seminar Group: 


Professor Tyrel M. McQueen


Department of Chemistry and Department of Physics and Astronomy
Johns Hopkins University


Monday, August 6, 2012 - 4:00pm


MRL Room 2053

Correlated electronic systems, or materials in which electrons show cooperative behavior rather than acting independently, have been of interest for many years. One of the most striking examples of such behavior is the ability of certain compounds, when cooled sufficiently, to carry electricity with zero resistance. The origin of such superconductivity at high temperatures in all known material classes remains controversial. In the case of the iron-based superconductors, which are based on two dimensional layers of edge-sharing [FeX4] (X = Se,As,P) tetrahedra, even the origin of magnetic and metallic ground states of non-superconducting parent compounds is contested, with apparently conflicting results on different material families. In this talk, I will present an overview of the state of the field, and our recent discovery that the reduced dimensionality spin-ladder compounds Ba{1- x}K{x}Fe2Se3, which are built of double-chains of edge-sharing [FeSe4] tetrahedra, are in fact ideal model systems in which to understand the interplay of charge and spin degrees of freedom in these fascinating compounds.