High energy-resolution inelastic neutron scattering experiments on triplet bound state excitations in SrCu2(BO3)2

• Published in: Journal of the Physical Society of Japan 2005-08, Vol.74 (8), p.2189-2192
• Main Authors: ASO, Naofumi, KAGEYAMA, Hiroshi, NUKUI, Katsuyuki, NISHI, Masakazu, KADOWAKI, Hiroaki, UEDA, Yutaka, KAKURAI, Kazuhisa
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
• ISSN: 0031-9015; 1347-4073

In this letter we report on the high energy-resolution neutron scattering studies on the dynamic structure factor of the two-triplet bound states in the two-dimensional S=1/2 Shastry-Sutherland system, SrCu2(BO3)2, in the energy transfer range of 4 to 7 meV. In contrast to the earlier interpretation of the low energy-resolution results, these bound state excitations show hardly any dispersion, but do show a strong wave-vector-dependent structure factor. Although these findings are in overall agreement with the recent theoretical calculation of the 2-triplon dynamic structure factor by Knetter and Uhrig [Phys. Rev. Lett. 92 (2004) 027204], they also show distinct differences, which may be due to some symmetry-breaking terms in the Hamiltonian that are not included in the theory, such as the interdimer Dzyaloshinski-Moriya interactions recently discovered in this compound.