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arXiv · 2212.03318

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

N. Aucar Boidi·Christian Helman·Y. Núñez-Fernández·K. Hallberg·A. A. Aligia
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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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N. Aucar Boidi, Christian Helman, Y. Núñez-Fernández, K. Hallberg, A. A. Aligia. 2022-12-06. Determination of superexchange interactions for the CuO$_2$ chains in LiCu$_2$O$_2$. https://doi.org/10.1103/physrevb.107.085128

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