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Magnetic Superstructure in the Two-Dimensional Quantum Antiferromagnet SrCu2(BO3)2

K. Kodama·M. Takigawa·M. Horvatic·C. Berthier·H. Kageyama·Y. Ueda·S. Miyahara·F. Becca·F. Mila
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Abstract

We report the observation of magnetic superstructure in a magnetization plateau state of SrCu2(BO3)2, a frustrated quasi-two-dimensional quantum spin system. The Cu and B nuclear magnetic resonance (NMR) spectra at 35 mllikelvin indicate an apparently discontinuous phase transition from uniform magnetization to a modulated superstructure near 27 tesla, above which a magnetization plateau at 1/8 of the full saturation has been observed. Comparison of the Cu NMR spectrum and the theoretical analysis of a Heisenberg spin model demonstrates the crystallization of itinerant triplets in the plateau phase within a large rhomboid unit cell (16 spins per layer) showing oscillations of the spin polarization. Thus we are now in possession of an interesting model system to study a localization transition of strongly interacting quantum particles.

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K. Kodama, M. Takigawa, M. Horvatic, C. Berthier, H. Kageyama, Y. Ueda, S. Miyahara, F. Becca, F. Mila. 2002-10-14. Magnetic Superstructure in the Two-Dimensional Quantum Antiferromagnet SrCu2(BO3)2. https://doi.org/10.1126/science.1075045

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