Direct evidence for the localized single-triplet excitations and the dispersive multitriplet excitations in SrCu2(BO3)2.
We performed inelastic neutron scattering on the 2D Shastry-Sutherland system SrCu2(11BO3)2 with an exact dimer ground state. Three energy levels at around 3, 5, and 9 meV were observed at 1.7 K. The lowest excitation at 3.0 meV is almost dispersionless with a bandwidth of 0.2 meV at most, showing a significant constraint on a single-triplet hopping owing to the orthogonality of the neighboring dimers. In contrast, the correlated two-triplet excitations at 5 meV exhibit a more dispersive behavior.
Kageyama
H
H
Material Design and Characterization Laboratory, Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan. kage@issp.u-tokyo.ac.jp
Nishi
M
M
Aso
N
N
Onizuka
K
K
Yosihama
T
T
Nukui
K
K
Kodama
K
K
Kakurai
K
K
Ueda
Y
Y