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arXiv · 0912.4741

Band Narrowing and Mott Localization in Iron Oxychalcogenides La2O2Fe2O(Se,S)2

Jian-Xin Zhu·Rong Yu·Hangdong Wang·Liang L. Zhao·M. D. Jones·Jianhui Dai·Elihu Abrahams·E. Morosan·Minghu Fang·Qimiao Si
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Abstract

Bad metal properties have motivated a description of the parent iron pnictides as correlated metals on the verge of Mott localization. What has been unclear is whether interactions can push these and related compounds to the Mott insulating side of the phase diagram. Here we consider the iron oxychalcogenides La2O2Fe2O(Se,S)2, which contain an Fe square lattice with an expanded unit cell. We show theoretically that they contain enhanced correlation effects through band narrowing compared to LaOFeAs, and we provide experimental evidence that they are Mott insulators with moderate charge gaps. We also discuss the magnetic properties in terms of a Heisenberg model with frustrating J1-J2-J2' exchange interactions on a "doubled" checkerboard lattice.

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Jian-Xin Zhu, Rong Yu, Hangdong Wang, Liang L. Zhao, M. D. Jones, Jianhui Dai, Elihu Abrahams, E. Morosan, Minghu Fang, Qimiao Si. 2010-05-07. Band Narrowing and Mott Localization in Iron Oxychalcogenides La2O2Fe2O(Se,S)2. https://doi.org/10.1103/physrevlett.104.216405

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