Elementary excitations and specific heat in quantum sine-Gordon spin chain KCuGaF6

Izumi Umegaki, Toshio Ono, Hidekazu Tanaka, Masaki Oshikawa, Hiroyuki Nojiri

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Elementary excitations of an S=1/2 antiferromagnetic Heisenberg chain KCuGaF6 were investigated through specific heat and electron spin resonance (ESR) measurements. In this compound, a staggered field is induced perpendicular to the external field because of the alternating g tensor and the DzyaloshinskyMoriya interaction with an alternating D vector. Such a spin system can be mapped onto the quantum sine-Gordon (SG) model, when subjected to the external magnetic field. Specific heat shows clear evidence of the field-induced gap, which is related to the elementary excitations, solitons and breathers, characteristic of the quantum SG model. q=0 excitations originated from solitons and breathers were directly observed by high-frequency high-field ESR. These experimental results are well described by the quantum SG field theory.

Original languageEnglish
Pages (from-to)741-747
Number of pages7
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Issue number3
Publication statusPublished - 2011 Jan

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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