Competing magnetic orders and multipolar Weyl fermions in 227 pyrochlore iridates

Abstract

Owing to comparably strong spin-orbit coupling and Hubbard interaction, iridium based 227 pyrochlore oxides harbor a rich confluence of competing magnetic orders and emergent multipolar Weyl quasiparticles. Here we show that this family of materials is predominantly susceptible toward the nucleation of electronic noncoplanar all-in all-out (AIAO) and three-in one-out (3I1O) orders, respectively transforming under the singlet $A_{2u}$ and triplet $T_{1u}$ representations, supporting octupolar and dipolar Weyl fermions, and favored by strong on-site Hubbard and nearest-neighbor ferromagnetic interaction. Furthermore, a coplanar magnetic order generically appears as an intermediate phase between them. This order transforms under the triplet $T_{2u}$ representation and also hosts octupolar Weyl fermions. With the AIAO and 3I1O phases possibly being realized in (Nd${}_{1-x}$Pr${}_x$)${}_2$Ir${}_2$O${}_7$ when $x=0$ and 1, respectively, the intervening $T_{2u}$ order can in principle be found at an intermediate doping ($0<x<1$) or in pressured (hydrostatic) Nd${}_2$Ir${}_2$O${}_7$.

Published version: 6 Pages, 3 Figures (Supplemental Materials: As ancillary file)

References in corpus (10)

• SU(2) Non-Abelian Holonomy and Dissipationless Spin Current in Semiconductors
• Theory of interacting electrons on the honeycomb lattice
• Multipole expansion for magnetic structures: A generation scheme for symmetry-adapted orthonormal basis set in crystallographic point group
• Emergent topological phenomena in thin films of pyrochlore iridates
• A New Type of Quantum Criticality in the Pyrochlore Iridates
• Pyrochlore electrons under pressure, heat and field: shedding light on the iridates
• Topological phases in layered pyrochlore oxide thin films along the [111] direction
• Anisotropy induces non-Fermi-liquid behavior and nematic magnetic order in three-dimensional Luttinger semimetals
• Evolution of possible Weyl semimetal states across the hole-doping induced Mott transition in pyrochlore iridates
• Monopole-limited nucleation of magnetism in Eu${}_2$Ir${}_2$O${}_7$

Cited by in corpus (6)

• Weyl-Luttinger phase transition in pyrochlore iridates revealed by Raman scattering
• Quasiuniversality from all-in-all-out Weyl quantum criticality in pyrochlore iridates
• Continuous order-to-order quantum phase transitions from fixed-point annihilation
• Anisotropic marginal Fermi liquid for Coulomb interacting generalized Weyl fermions
• Axionic quantum criticality of generalized Weyl semimetals
• Ferromagnetic fragmented state in the pyrochlore Ho${}_2$Ru${}_2$O${}_7$