Direct Evidence for the Localized Single-Triplet Excitations and the Dispersive Multitriplet Excitations in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>SrCu</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mo>(</mo><mrow><msub><mrow><mi>BO</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow><mrow><msub><mrow><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>

H. Kageyama; M. Nishi; N. Aso; K. Onizuka; T. Yosihama; K. Nukui; K. Kodama; K. Kakurai; Y. Ueda

doi:10.1103/PhysRevLett.84.5876

Direct Evidence for the Localized Single-Triplet Excitations and the Dispersive Multitriplet Excitations in ${SrCu}_{2} ({BO}_{3})_{2}$

H. Kageyama, M. Nishi, N. Aso, K. Onizuka, T. Yosihama, K. Nukui, K. Kodama, K. Kakurai, and Y. Ueda

Phys. Rev. Lett. 84, 5876 – Published 19 June 2000

Abstract

We performed inelastic neutron scattering on the 2D Shastry-Sutherland system $SrCu_{2} (^{11} BO_{3})_{2}$ 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.

Received 17 September 1999

DOI:https://doi.org/10.1103/PhysRevLett.84.5876

Authors & Affiliations

H. Kageyama^1,*, M. Nishi², N. Aso², K. Onizuka¹, T. Yosihama², K. Nukui², K. Kodama³, K. Kakurai², and Y. Ueda¹

¹Material Design and Characterization Laboratory, Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
²Neutron Scattering Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
³Division of New Materials Science, Institute for Solid State Physics, University of Tokyo, Roppongi, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan