LaMnO$_3$ is a Mott Insulator: an precise definition and an evaluation of the local interaction strength

TL;DR

This paper precisely defines LaMnO$_3$ as a Mott insulator by comparing measured interaction parameters to theoretical critical values, highlighting the role of electron-electron and electron-lattice interactions in its insulating state.

Contribution

It provides a detailed comparison of experimental interaction parameters with dynamical mean field theory estimates to clarify the Mott insulating nature of LaMnO$_3$.

Findings

Total correlation strength slightly exceeds the critical value for a Mott transition.

Neglecting electron-lattice interactions predicts metallic behavior.

Additional physics like Mn-O-Mn bond buckling influences the insulating state.

Abstract

We compare the interaction parameters measured on LaMnO$_3$ to single site dynamical mean field estimates of the critical correlation strength needed to drive a Mott transition, finding that the total correlation strength (electron-electron plus electron-lattice) is very close to but slightly larger than the critical value, while if the electron lattice interaction is neglected the model is metallic. Our results emphasize the importance of additional physics including the buckling of the Mn-O-Mn bonds.