In-Gap Spin Excitations and Finite Triplet Lifetimes in the Dilute Singlet Ground State SystemSrCu2−xMgx(BO3)2 Academic Article uri icon

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abstract

  • High resolution neutron scattering measurements on a single crystal of SrCu(2-x)Mgx(BO3)2 with x approximately 0.05 reveal the presence of new spin excitations within the gap of this quasi-two-dimensional, singlet ground state system. The application of a magnetic field induces Zeeman-split states associated with S=1/2 unpaired spins which are antiferromagnetically correlated with the bulk singlet. Substantial broadening of both the one- and two-triplet excitations in the doped single crystal is observed, as compared with pure SrCu2(BO3)2. Theoretical calculations using a variational algorithm and a single quenched magnetic vacancy on an infinite lattice are shown to qualitatively account for these effects.

authors

  • Haravifard, S
  • Dunsiger, SR
  • El Shawish, S
  • Gaulin, Bruce D
  • Dabkowska, HA
  • Telling, MTF
  • Perring, TG
  • Bonča, J

publication date

  • December 15, 2006