Spin-Triplet Excitons in the $S=1/2$ Gapped Antiferromagnet BaCuSi$_2$O$_6$: Electron Paramagnetic Resonance Studies

S. A. Zvyagin; J. Wosnitza; J. Krzystek; R. Stern; M. Jaime; Y. Sasago; K. Uchinokura

doi:10.1103/PHYSREVB.73.094446

paper

Spin-Triplet Excitons in the $S = 1/2$ Gapped Antiferromagnet BaCuSi $_{2}$ O $_{6}$ : Electron Paramagnetic Resonance Studies

arXiv:cond-mat/0601017 · doi:10.1103/PHYSREVB.73.094446

Abstract

BaCuSi $_{2}$ O $_{6}$ , a $S = 1/2$ quantum antiferromagnet with a double-layer structure of Cu $^{2 +}$ ions in a distorted planar-rectangular coordination and with a dimerized spin singlet ground state, is studied by means of the electron paramagnetic resonance technique. It is argued that multiple absorptions observed at low temperatures are intimately related to a thermally-activated spin-triplet exciton superstructure. Analysis of the angular dependence of exciton modes in BaCuSi $_{2}$ O $_{6}$ allows us to accurately estimate anisotropy parameters. In addition, the temperature dependence of EPR intensity and linewidth is discussed.

Submitted to Phys. Rev. B

Spin-Triplet Excitons in the S=1/2 Gapped Antiferromagnet BaCuSi2​O6​: Electron Paramagnetic Resonance Studies

Abstract

Spin-Triplet Excitons in the $S = 1/2$ Gapped Antiferromagnet BaCuSi $_{2}$ O $_{6}$ : Electron Paramagnetic Resonance Studies