Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2010 May 28;104(21):216405. doi: 10.1103/PhysRevLett.104.216405.
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.
不良的金属性质促使人们将母体铁磷化物描述为处于莫特局域化边缘的相关金属。一直不清楚的是，相互作用是否可以将这些和相关化合物推向相图的莫特绝缘侧。在这里，我们考虑了铁氧硫属化物 La2O2Fe2O(Se,S)2，它包含一个具有扩展单元的 Fe 正方形晶格。我们从理论上表明，与 LaOFeAs 相比，它们通过能带变窄包含增强的关联效应，并且我们提供了实验证据表明它们是具有中等电荷间隙的莫特绝缘体。我们还根据具有在“加倍”棋盘格晶格上的受挫 J1-J2-J2'交换相互作用的海森堡模型讨论了磁性性质。
