Related Experiment Video
Updated: Jun 8, 2026

Fabrication of Spatially Confined Complex Oxides
Published on: July 1, 2013
Band narrowing and Mott localization in iron oxychalcogenides La2O2Fe2O(Se,S)2
Jian-Xin Zhu1, Rong Yu, Hangdong Wang
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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.
Related Concept Videos
Ferromagnetism
Valence Bond Theory
Molecular Orbital Theory II
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Biasing of Metal-Semiconductor Junctions
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...

