The Anti-Jahn-Teller Polaron in LaMnO$_3$

TL;DR

This paper introduces a model explaining how anti-Jahn-Teller polarons form in LaMnO₃, shedding light on the material's magnetic and electronic phase transitions upon doping.

Contribution

It presents a simple, predictive model for anti-Jahn-Teller polarons and their role in phase transitions in LaMnO₃ without requiring parameter adjustments.

Findings

Predicts shape and stability of anti-Jahn-Teller polarons

Provides a new description of doping effects on magnetic states

Explains metal-insulator transition mechanisms

Abstract

Distortions of the oxygen sublattice couple to $e_g$ orbitals of Mn$^{3+}$ and drive a cooperative Jahn-Teller (orbital ordering) transition in LaMnO$_3$. A simple model for this transition is studied. Without further adjustment, the model predicts the shape and stability of small (anti-Jahn-Teller) polarons which form when holes are doped into the material. This leads to a new description of the lightly doped insulator, the anti-ferromagnetic to ferromagnetic transition, and the metal-insulator transition.