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TT: Fachverband Tiefe Temperaturen

TT 23: Correlated Electrons: (General) Theory

TT 23.7: Vortrag

Mittwoch, 27. Februar 2008, 15:45–16:00, H 0104

Plateaux and supersolid phases in SrCu₂(BO₃)₂ — •Kai P. Schmidt, Julien Dorier, and Frederic Mila — Institute of Theoretical Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland

In a magnetic field, SrCu₂(BO₃)₂ displays magnetization plateaux at fractional fillings 1/8, 1/4 and 1/3. This work aims at a microscopic description of these plateaux, and investigate the behavior around these plateaux focussing on possible supersolid phases.

Using series expansion techniques, we have derived a realistic hard-core boson model which is dominated by long-range repulsive interactions and correlated hopping. We investigate the properties of this model by a classical approximation based on a spin representation. While the long-range interactions stabilize solid phases at fractional fillings (magnetization plateaux), the correlated hopping favours supersolid phases. This interplay between interactions and kinetics leads to a rich phase diagram with solid, superfluid, and supersolid competing phases.