Spin Singlet Formation from S = 1/2 Tetrahedral Clusters

T. Waki; Y. Kajinami; Y. Tabata; M. Yoshida; M. Takigawa; I. Watanabe; H. Nakamura

Spin Singlet Formation from S = 1/2 Tetrahedral Clusters

Materials Science 2009-06-30 v1

Authors: T. Waki , Y. Kajinami , Y. Tabata , M. Yoshida , M. Takigawa , I. Watanabe , H. Nakamura

Abstract

Muon spin relaxation ( $\mu$ SR) and nuclear magnetic resonance (NMR) experiments revealed that the spin singlet state with an excitation gap of $\sim$ 200 K is realized from $S = 1/2$ Nb $_4$ tetrahedral clusters in a cluster Mott insulator GaNb $_4$ S $_8$ . The intercluster cooperative phenomenon to the singlet state at $T_\mathrm{S} = 32$ K is triggered by intracluster Jahn-Teller type structural instability developed from $\sim$ $3T_\mathrm{S}$ . Referring to the lattice symmetry, the formation of Nb $_8$ octamer (Nb $_4$ --Nb $_4$ bond) is suggested.

Keywords

spin chains

Cite

@article{arxiv.0906.5116,
  title  = {Spin Singlet Formation from S = 1/2 Tetrahedral Clusters},
  author = {T. Waki and Y. Kajinami and Y. Tabata and M. Yoshida and M. Takigawa and I. Watanabe and H. Nakamura},
  journal= {arXiv preprint arXiv:0906.5116},
  year   = {2009}
}

Comments

11 pages, 5figures

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