ESR study on the excited state energy spectrum of SrCu2(BO 3)2 - A central role of multiple-triplet bound states

Hiroyuki Nojiri, Hiroshi Kageyama, Yutaka Ueda, Mitsuhiro Motokawa

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52 Citations (Scopus)


The excited state energy spectrum of a two-dimensional dimer system SrCu2(BO3)2 has been investigated by high field ESR. Besides two non-degenerated one-triplet excitations, various types of multiple-triplet bound states are identified: singlet, triplet, and quintet. The intensity of these bound states is extremely strong because one-triplet process is strongly suppressed in the orthogonal dimer system. The bound singlet state is found slightly below the energy gap of the one-triplet state, indicating the proximity to a quantum critical point. A band of the two-triplet bound state splits due to distant neighbor interactions. The bound quintet state is the direct evidence of two-triplet object made up of four S = 1/2 spins. The energy of the lowest quintet becomes lower than that of the one-triplet excitation before the closing of the lowest spin gap, namely, the quintet touches first to the ground singlet state. The present investigation exhibits an essential role of multiple-triplet bound states in the magnetic excitation spectrum.

Original languageEnglish
Pages (from-to)3243-3253
Number of pages11
Journaljournal of the physical society of japan
Issue number12
Publication statusPublished - 2003 Dec
Externally publishedYes


  • ESR
  • High magnetic field
  • Magnetic excitation
  • Spin gap
  • SrCu(BO)

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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