Determination of superexchange interactions for the CuO${}_2$ chains in LiCu${}_2$O${}_2$

Abstract

Starting from \textit{ab-initio} calculations, we derive a five-band Hubbard model to describe the CuO${}_2$ chains of LiCu${}_2$O${}_2$. This model is further simplified to a low-energy effective Heisenberg model with nearest-neighbor (NN) $J_1$, and next-nearest-neighbor (NNN) $J_2$ interactions, combining perturbation theory, exact diagonalization calculations and Density Matrix Renormalization Group results. For realistic parameters we find the corresponding values of these interactions. The obtained effective model is consistent with a spiral-magnetic ground state as experimentally observed. Using symmetry arguments, the spiral state is a sufficient condition for the ferroelectricity observed in the system.

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Cited by in corpus (1)

• Structural transition, spontaneous formation of strong singlet dimers and metamagnetism in $S=3/2$ magnetoelastic spin chains