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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons: Spin Systems and Itinerant Magnets - Frustrated Magnets II

TT 20.4: Vortrag

Montag, 31. März 2014, 15:45–16:00, HSZ 304

The 2D Shastry-Sutherland model and SrCu₂(BO₃)₂ in Magnetic Fields up to 118T — •Andreas Honecker¹, Philippe Corboz², Frédéric Mila³, HongYu Yang³, Salvatore R. Manmana¹, Kai P. Schmidt⁴, Gregor R. Foltin⁴, Hiroshi Kageyama⁵, Nozomu Abe⁶, Shojiro Takeyama⁶, and Yasuhiro Matsuda⁶ — ¹Georg-August-Universität Göttingen, Germany — ²ETH Zürich, Switzerland — ³Ecole Polytechnique Fédérale de Lausanne, Switzerland — ⁴TU Dortmund, Germany — ⁵Kyoto University, Japan — ⁶ISSP, University of Tokyo, Japan

The magnetization process of the orthogonal-dimer antiferromagnet SrCu₂(BO₃)₂ is investigated in high magnetic fields of up to 118T. A 1/2 plateau is clearly observed in the field range 84 to 108T in addition to 1/3, 1/4, and 1/8 plateaux at lower fields. Using a combination of state-of-the-art numerical simulations, the main features of the high-field magnetization curve are shown to agree quantitatively with the Shastry-Sutherland model for a ratio of inter- to intra-dimer exchange interactions J^′/ J =0.63. It is further predicted that the intermediate phase between the 1/3 and 1/2 plateau consists of a 1/3 supersolid followed by a non-plateau 2/5 supersolid. As a byproduct, we obtain estimates for the boundaries of a zero-field plaquette phase based on exact diagonalization with up to N=40 sites.