Multiple Magnon Modes and Consequences for the Bose-Einstein Condensed Phase in BaCuSi2O6

Abstract

The compound BaCuSi2O6 is a quantum magnet with antiferromagnetic dimers of S = 1/2 moments on a quasi-2D square lattice. We have investigated its spin dynamics by inelastic neutron scattering experiments on single crystals with an energy resolution considerably higher than in an earlier study. We observe multiple magnon modes, indicating clearly the presence of magnetically inequivalent dimer sites. This more complex spin Hamiltonian leads to a distinct form of magnon Bose-Einstein condensate (BEC) phase with a spatially modulated condensate amplitude.

5 pages, 4 figures, to be published in Phys. Rev. Lett

References in corpus (2)

• Dimensional reduction at a quantum critical point
• Spin-resonance modes of the spin-gap magnet TlCuCl_3

Cited by in corpus (8)

• Bose-Einstein Condensation in Magnetic Insulators
• Geometric Frustration and Dimensional Reduction at a Quantum Critical Point
• Ordered magnetic phases of the frustrated spin-dimer compound Ba3Mn2O8
• Theory of the field-induced BEC in the frustrated spin-1/2 dimer compound BaCuSi2O6
• NMR evidence for a strong modulation of the Bose-Einstein Condensate in BaCuSi${}_2$O${}_6$
• Quantum phase transitions and dimensional reduction in antiferromagnets with inter-layer frustration
• Magnetic excitations in the spin-trimer compounds Ca3Cu3-xNix(PO4)4 (x=0,1,2)
• Reduced dimensionality in layered quantum dimer magnets: Frustration vs. inhomogeneous condensates