2002/10/14 by K. Kodama, M. Takigawa, M. Horvatic +6 · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1126/science.1075045
published as Science vol. 298, page 395, year 2002 · PDF file, 16 pages, 5 figures
arxiv created 2002/10/14 · arxiv updated 2009/11/30
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.