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arXiv · 0712.0926

Field dependence of the quantum ground state in the Shastry-Sutherland system SrCu$_2$(BO$_3$)$_2$

F. Levy·I. Sheikin·C. Berthier·M. Horvatic·M. Takigawa·H. Kageyama·T. Waki·Y. Ueda
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Abstract

We present magnetic torque measurements on the Shastry-Sutherland quantum spin system SrCu$_2$(BO$_3$)$_2$ in fields up to 31 T and temperatures down to 50 mK. A new quantum phase is observed in a 1 T field range above the 1/8 plateau, in agreement with recent NMR results. Since the presence of the DM coupling precludes the existence of a true Bose-Einstein condensation and the formation of a supersolid phase in SrCu$_2$(BO$_3$)$_2$, the exact nature of the new phase in the vicinity of the plateau remains to be explained. Comparison between magnetization and torque data reveals a huge contribution of the Dzyaloshinskii-Moriya interaction to the torque response. Finally, our measurements demonstrate the existence of a supercooling due to adiabatic magnetocaloric effects in pulsed field experiments.

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F. Levy, I. Sheikin, C. Berthier, M. Horvatic, M. Takigawa, H. Kageyama, T. Waki, Y. Ueda. 2007-12-06. Field dependence of the quantum ground state in the Shastry-Sutherland system SrCu$_2$(BO$_3$)$_2$. https://doi.org/10.1209/0295-5075/81/67004

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