Uniaxial pressure induced half-metallic ferromagnetic phase transition in LaMnO$_3$

TL;DR

Applying uniaxial pressure to LaMnO₃ induces a phase transition from an antiferromagnetic insulator to a ferromagnetic half-metal, driven primarily by Jahn-Teller mode changes, enabling potential colossal magnetoresistance at lower pressures.

Contribution

This study predicts a novel pressure-induced phase transition in LaMnO₃ using first-principles calculations, highlighting the role of Jahn-Teller modes in tuning magnetic and electronic properties.

Findings

Uniaxial pressure induces a ferromagnetic half-metallic phase in LaMnO₃.

The transition is driven mainly by the Q2 Jahn-Teller mode.

Half-metallicity could enable colossal magnetoresistance at lower pressures.

Abstract

We use first-principles theory to predict that the application of uniaxial compressive strain leads to a transition from an antiferromagnetic insulator to a ferromagnetic half-metal phase in LaMnO$_3$. We identify the Q2 Jahn-Teller mode as the primary mechanism that drives the transition, indicating that this mode can be used to tune the lattice, charge, and spin coupling. Applying $\simeq$ 6 GPa of uniaxial pressure along the [010] direction activates the transition to a half-metallic $\textit{pseudo-cubic}$ state. The half-metallicity opens the possibility of producing colossal magnetoresistance in the stoichiometric LaMnO$_3$ compound at significantly lower pressure compared to recently observed investigations using hydrostatic pressure.