Microscopic model for the structural transition and spin gap formation in alpha(')-NaV2O5

  title={Microscopic model for the structural transition and spin gap formation in alpha(')-NaV2O5},
  author={A. Bernert and Peter Thalmeier and Peter Fulde},
  journal={Physical Review B},
We present a microscopic model for α'-NaV 2 O 5 . Using an extended Hubbard model for the vanadium layers we derive an effective low-energy model consisting of pseudospin Ising chains and Heisenberg chains coupled to each other. We find a "spin-Peierls-Ising" phase transition which causes charge ordering on every second ladder and superexchange alternation on the other ladders. This transition can be identified with the first transition of the two close-by transitions observed in experiment… 
5 Citations
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Structure determination, valence, and superexchange in the dimerized low temperature phase of α′- NaV2O5
Abstract:We report results of a new analysis for the low-temperature structure of α′-NaV2O5 from synchrotron X-ray diffraction experiments. We confirm the existence of two inequivalent ladder
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Charge-order-driven spin-peierls transition in alpha(')-NaxV2O5
A charge-ordering transition starting at T</=37 K and preceding the lattice distortion and the formation of a spin gap Delta = 106 K at T(c) = 34.7 K is concluded.
Effective charge and spin Hamiltonian for the quarter-filled ladder compound α'-NaV2O5
Abstract:An effective intra- and inter-ladder charge-spin Hamiltonian for the quarter-filled ladder compound α'-NaV2O5 has been derived by using the standard canonical transformation method. In the
Test of the frustrated spin-cluster model to describe the low-temperature physics of NaV 2 O 5
investigate a spin cluster model, consisting of weakly coupled, frustrated four-spin clusters aligned along the crystallographic b axis that was recently proposed to reconcile these experimental
Superexchange in the quarter-filled two-leg ladder system NaV2O5.
A theory of superexchange in the mixed valent layer compound NaV2O5 is presented which provides a consistent description of exchange both in the disordered and charge ordered state. Starting from
Charge ordering and spin-Peierls transition in α' − NaV2O5
Recent X-ray analysis and NMR experiments have shown that α' − NaV2O5 is not a conventional spin-Peierls (SP) compound because above the transition at 33 K it is in a homogeneous mixed valent (MV)
A new view of the electronic structure of the spin-Peierls compound -NaVO
Abstract:The present understanding of the electronic and magnetic properties of -NaV2O5 is based on the hypothesis of strong charge disproportionation into V4+ and V5+, which is assumed to lead to a