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arXiv · 1511.09195

Strong charge and spin fluctuations in La$_2$O$_3$Fe$_2$Se$_2$

Guangxi Jin·Yilin Wang·Xi Dai·Xinguo Ren·Lixin He
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Abstract

The electronic structure and magnetic properties of the strongly correlated material La$_2$O$_3$Fe$_2$Se$_2$ are studied by using both the density function theory plus $U$ (DFT+$U$) method and the DFT plus Gutzwiller (DFT+G) variational method. The ground-state magnetic structure of this material obtained with DFT+$U$ is consistent with recent experiments, but its band gap is significantly overestimated by DFT+$U$, even with a small Hubbard $U$ value. In contrast, the DFT+G method yields a band gap of 0.1 - 0.2 eV, in excellent agreement with experiment. Detailed analysis shows that the electronic and magnetic properties of of La$_2$O$_3$Fe$_2$Se$_2$ are strongly affected by charge and spin fluctuations which are missing in the DFT+$U$ method.

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Guangxi Jin, Yilin Wang, Xi Dai, Xinguo Ren, Lixin He. 2015-11-30. Strong charge and spin fluctuations in La$_2$O$_3$Fe$_2$Se$_2$. https://doi.org/10.1103/physrevb.94.075150

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