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On the presence of mid-gap states in CaV4O9

Marc Albrecht·Frederic Mila·Didier Poilblanc
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Abstract

Using exact diagonalizations of finite clusters with up to 32 sites, we study the $J_1-J_2$ model on the 1/5 depleted square lattice. Spin-spin correlation functions are consistent with plaquette order in the spin gap phase which exists for intermediate values of $J_2/J_1$. Besides, we show that singlet states will be present in the singlet-triplet gap if $J_2/J_1$ is not too small ($J_2/J_1 \gtrsim 0.47$). We argue that this property should play a central role in determining the exchange integrals in ${\rm CaV}_4{\rm O}_9$

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Marc Albrecht, Frederic Mila, Didier Poilblanc. 1996-06-17. On the presence of mid-gap states in CaV4O9. https://doi.org/10.1103/physrevb.54.15856

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