Elementary excitations of the S= 1 2 one-dimensional antiferromagnet KCuGaF6 in a magnetic field and quantum sine-Gordon model

Izumi Umegaki, Hidekazu Tanaka, Toshio Ono, Hidehiro Uekusa, Hiroyuki Nojiri

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Elementary excitations of the S= 1 2 one-dimensional Heisenberg antiferromagnet KCuGaF6 with exchange constant J/ kB =103 K were investigated by high-frequency electron spin resonance (ESR) measurements combined with a pulsed high magnetic field. When an external magnetic field H is applied in KCuGaF6, a staggered magnetic field h is induced perpendicular to H owing to the staggered g tensor and the Dzyaloshinsky-Moriya (DM) interaction with an alternating D vector. Consequently, KCuGaF6 in a magnetic field is represented by the quantum sine-Gordon (SG) model. We observed many resonance modes including a soliton resonance, breathers, interbreather transitions, and two-breather excitation. Their resonance conditions are beautifully described by the quantum SG field theory with one adjustable parameter cs =h/H. To investigate the relationship between the Curie term due to the DM interaction and the proportionality coefficient cs, magnetic susceptibility measurements were also performed varying the external field direction.

Original languageEnglish
Article number184401
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number18
DOIs
Publication statusPublished - 2009 May 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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