Theory of Multifarious Quantum Phases and Large Anomalous Hall effect in Pyrochlore Iridate Thin Films

TL;DR

This paper models thin film pyrochlore iridates to predict emergent quantum phases, including magnetic metal states with large anomalous Hall effects, arising from layer-dependent magnetic structures and electron interactions.

Contribution

It introduces a theoretical model for layer-dependent magnetic structures in pyrochlore iridate thin films, revealing novel magnetic metal phases with large anomalous Hall effects.

Findings

Magnetic order develops in inhomogeneous patterns across layers.

Thin films exhibit Weyl semimetal-like electronic states.

Large anomalous Hall effect is predicted in these phases.

Abstract

We theoretically investigate emergent quantum phases in the thin film geometries of the pyrochore iridates, where a number of exotic quantum ground states are proposed to occur in bulk materials as a result of the interplay between electron correlation and strong spin-orbit coupling. The fate of these bulk phases as well as novel quantum states that may arise only in the thin film platforms, are studied via a theoretical model that allows layer-dependent magnetic structures. It is found that the magnetic order develop in inhomogeneous fashions in the thin film geometries. This leads to a variety of magnetic metal phases with modulated magnetic ordering patterns across different layers. Both the bulk and boundary electronic states in these phases conspire to promote unusual electronic properties. In particular, such phases are akin to the Weyl semimetal phase in the bulk system and they would exhibit an unusually large anomalous Hall effect.