La$_2$O$_3$Fe$_2$Se$_2$, a Mott insulator on the brink of orbital-selective metalization
Gianluca Giovannetti, Luca de' Medici, Markus Aichhorn, Massimo Capone
TL;DR
La$_2$O$_3$Fe$_2$Se$_2$ is a Mott insulator driven by crystal-field effects, and can be tuned into an orbital-selective Mott state via doping or pressure, contrasting with metallic FeSe.
Contribution
This work identifies crystal-field splitting as the key factor for Mott insulating behavior in La$_2$O$_3$Fe$_2$Se$_2$ and predicts its transition to an orbital-selective Mott state under external perturbations.
Findings
La$_2$O$_3$Fe$_2$Se$_2$ is a Mott insulator due to crystal-field effects.
Enhanced crystal-field splitting pushes the material near an orbital-selective Mott transition.
Doping or pressure can induce an orbital-selective Mott state.
Abstract
LaOFeSe can be explained in terms of Mott localization in sharp contrast with the metallic behavior of FeSe and other parent parent compounds of iron superconductors. We demonstrate that the key ingredient that makes LaOFeSe a Mott insulator, rather than a correlated metal dominated by the Hund's coupling is the enhanced crystal-field splitting, accompanied by a smaller orbital-resolved kinetic energy. The strong deviation from orbital degeneracy introduced by the crystal-field splitting also pushes this materials close to an orbital-selective Mott transition. We predict that either doping or uniaxial external pressure can drive the material into an orbital-selective Mott state, where only one or few orbitals are metallized while the others remain insulating.
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.