Rüegg Ch, McMorrow D F, Normand B, Rønnow H M, Sebastian S E, Fisher I R, Batista C D, Gvasaliya S N, Niedermayer Ch, Stahn J
London Centre for Nanotechnology, Department of Physics and Astronomy, University College London, London, UK.
Phys Rev Lett. 2007 Jan 5;98(1):017202. doi: 10.1103/PhysRevLett.98.017202. Epub 2007 Jan 4.
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. The more complex spin Hamiltonian revealed in our study leads to a distinct form of magnon Bose-Einstein condensate phase with a spatially modulated condensate amplitude.
化合物BaCuSi2O6是一种量子磁体，在准二维正方晶格上具有S = 1/2磁矩的反铁磁二聚体。我们通过对单晶进行非弹性中子散射实验研究了其自旋动力学，该实验的能量分辨率比早期研究中的要高得多。我们观察到多个磁振子模式，清楚地表明存在磁不等价的二聚体位点。我们研究中揭示的更复杂的自旋哈密顿量导致了一种具有空间调制凝聚振幅的独特形式的磁振子玻色 - 爱因斯坦凝聚相。
