2001/02/28 by C. H. Chung, J. B. Marston, Subir Sachdev
Physics and Astronomy · #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.64.134407
published as Physical Review B 64, 134407 (2001) · 8 pages, 8 figures; (v2) added new appendix and references
arxiv created 2001/03/10 · arxiv updated 2009/11/30
We study possible paramagnetic phases of antiferromagnets on the Shastry-Sutherland lattice by a gauge-theoretic analysis of fluctuations in a theory with Sp(2N) symmetry. In addition to the familiar dimer phase, we find a confining phase with plaquette order, and a topologically ordered phase with deconfined S=1/2 spinons and helical spin correlations. The deconfined phase is contiguous to the dimer phase, and in a regime of couplings close to those found in the insulator SrCu2(BO3)2. We suggest that a superconductor obtained by doping this insulator with mobile charge carriers will be an attractive candidate for observing the anomalous magnetic flux properties associated with topological order.