Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 34: Correlated Electrons: Spin Systems and Itinerant Magnets

TT 34.7: Vortrag

Freitag, 31. März 2006, 11:45–12:00, HSZ 301

Orbital Ordering and Spin-Ladder Formation in La₂RuO₅ — •Volker Eyert, Stefan G. Ebbinghaus, and Thilo Kopp — Institut für Physik, Universität Augsburg

The semiconductor-semiconductor transition of La₂RuO₅ is studied by means of augmented spherical wave (ASW) electronic structure calculations as based on density functional theory and the local density approximation. This transition has lately been reported to lead to orbital ordering and a quenching of the local spin magnetic moment. Our results give strong hints for a different orbital ordering scenario than the one previously proposed. In our type of ordering, the local S = 1 moment at the Ru sites is preserved in the low-temperature phase. The unusual magnetic behaviour is interpreted by the formation of spin-ladders, which result from the structural changes occurring at the transition and are characterized by antiferromagnetic coupling along the rungs.