论文标题
cuo $ _2 $链中的superexchange交互的确定$ _2 $ o $ _2 $
Determination of superexchange interactions for the CuO$_2$ chains in LiCu$_2$O$_2$
论文作者
论文摘要
从\ textit {ab-initio}计算开始，我们得出了一个五频哈伯德模型来描述cuo $ _2 $ licu $ _2 $ o $ o $ $ _2 $的链条。该模型被进一步简化为与最近邻居（NN）$ J_1 $的低能有效的Heisenberg模型，以及下一个NEAREST-NEIGHBOR（NNN）$ J_2 $交互，结合了扰动理论，精确的斜应计算和密度密度矩阵重新构化组结果。对于现实参数，我们找到这些相互作用的相应值。所获得的有效模型与实验观察到的螺旋磁基态保持一致。使用对称参数，螺旋状态是在系统中观察到的铁电性的充分条件。
Starting from \textit{ab-initio} calculations, we derive a five-band Hubbard model to describe the CuO$_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.
