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arXiv · 0811.4745

Theory of the field-induced BEC in the frustrated spin-1/2 dimer compound BaCuSi2O6

Nicolas Laflorencie·Frederic Mila
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Abstract

Building on recent neutron and NMR experiments, we investigate the field-induced exotic criticality observed in the frustrated spin-1/2 dimer compound BaCuSi2O6 using a frustrated model with two types of bilayers. A semiclassical treatment of the effective hard-core boson model shows that perfect inter-layer frustration leads to a 2D-like critical exponent phi=1 without logarithmic corrections and to a 3D low temperature phase with different but non vanishing triplet populations in both types of bilayers. These results further suggest a simple phenomenology in terms of a field-dependent transverse coupling in the context of which we reproduce the entire field-temperature phase diagram with Quantum Monte Carlo simulations.

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Nicolas Laflorencie, Frederic Mila. 2009-02-16. Theory of the field-induced BEC in the frustrated spin-1/2 dimer compound BaCuSi2O6. https://doi.org/10.1103/physrevlett.102.060602

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