Magnon dispersion in the field-induced magnetically ordered phase of TlCuCl3

Phys Rev Lett. 2002 Aug 12;89(7):077203. doi: 10.1103/PhysRevLett.89.077203. Epub 2002 Jul 26.


The magnetic properties of the interacting dimer system TlCuCl3 are investigated within a bond-operator formulation. The observed field-induced staggered magnetic order perpendicular to the field is described as a Bose condensation of magnons which are linear combinations of dimer singlet and triplet modes. This technique accounts for the magnetization curve and for the field dependence of the magnon dispersion curves observed by high-field neutron scattering measurements.