Pyrochlore electrons under pressure, heat and field: shedding light on the iridates

TL;DR

This paper models pyrochlore iridates considering temperature, magnetic field, and pressure effects, revealing complex phase transitions and aligning well with experimental data, thus providing a comprehensive understanding of their electronic behavior.

Contribution

It introduces the most general symmetry-allowed Hamiltonian for pyrochlore iridates, including next-nearest neighbor hopping, unifying various phases and experimental observations.

Findings

Identifies Lifshitz and thermal transitions between multiple electronic phases.

Predicts charge conductivity, Hall effect, and magnetic responses consistent with experiments.

Provides new theoretical predictions for pyrochlore iridates' phase behavior.

Abstract

We study the finite temperature and magnetic field phase diagram of electrons on the pyrochlore lattice subject to a local repulsion as a model for the pyrochlore iridates. We provide the most general symmetry-allowed Hamiltonian, including next-nearest neighbour hopping, and relate it to a Slater-Koster based Hamiltonian for the iridates. It captures Lifshitz and/or thermal transitions between several phases such as metals, semimetals, topological insulators and Weyl semimetals, and gapped antiferromagnets with different orders. Our results on the charge conductivity, both DC and optical, Hall coefficient, magnetization and susceptibility show good agreement with recent experiments and provide new predictions. As such, our effective model sheds light on the pyrochlore iridates in a unified way.