Tuesday, November 27, 2012

1211.5880 (Daisuke Yamamoto et al.)

Magnon Supersolid and Anomalous Hysteresis in Spin Dimers on a
Triangular Lattice

Daisuke Yamamoto, Ippei Danshita
We study the magnetic phase diagram and hysteresis behavior of weakly coupled spin dimers on a triangular lattice using the cluster mean-field method with cluster-size scaling. We find that the magnetization curve has plateaus at 1/3 and 2/3 of the total magnetization, in which local singlet and triplet states form a superlattice pattern. Moreover, if increasing (decreasing) the magnetic field from the 1/3 (2/3) plateau, the Bose-Einstein condensation (BEC) of triplons occurs on the superlattice background, leading to the transition into magnon supersolid phase. We also find that the first-order transition between these solid states and the standard magnon BEC state exhibits an anomalous hysteresis upon cycling the magnetic field; the transition can occur only from solid to BEC, and the system cannot return to the initial solid state in the reverse process.
View original: http://arxiv.org/abs/1211.5880

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