Orbital ordering promotes weakly-interacting S=1/2 dimers in the triangular lattice compound Sr3Cr2O8

L. C. Chapon; C. Stock; P. G. Radaelli; C. Martin

Orbital ordering promotes weakly-interacting S=1/2 dimers in the triangular lattice compound Sr3Cr2O8

Materials Science 2008-07-10 v2 Strongly Correlated Electrons

Authors: L. C. Chapon , C. Stock , P. G. Radaelli , C. Martin

Abstract

The weakly interacting S=1/2 dimers system Sr3Cr2O8 has been investigated by powder neutron diffraction and inelastic neutron scattering. Our data reveal a structural phase transition below room temperature corresponding to an antiferro-orbital ordering with nearly 90 degrees arrangement of the occupied 3z^2-r^2 d-orbital. This configuration leads to a drastic reduction of the inter-dimer exchange energies with respect to the high temperature orbital-disorder state, as shown by a spin-dimer analysis of the super-superexchange interactions performed using the Extended Huckel Tight Binding method. Inelastic neutron scattering reveals the presence of a quasi non-dispersive magnetic excitation at 5.4 meV, in agreement with the picture of weakly-interacting dimers.

Keywords

charge ordering frustrated magnetism phase transitions

Cite

@article{arxiv.0807.0877,
  title  = {Orbital ordering promotes weakly-interacting S=1/2 dimers in the triangular lattice compound Sr3Cr2O8},
  author = {L. C. Chapon and C. Stock and P. G. Radaelli and C. Martin},
  journal= {arXiv preprint arXiv:0807.0877},
  year   = {2008}
}

Orbital ordering promotes weakly-interacting S=1/2 dimers in the triangular lattice compound Sr3Cr2O8

Abstract

Keywords

Cite

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