Symmetry-enforced heavy-fermion physics in the quadruple-perovskite CaCu3Ir4O12

TL;DR

This paper proposes a symmetry-based mechanism in CaCu3Ir4O12 that enforces heavy-fermion behavior in d-electron systems by restricting electron hoppings, offering insights for designing new heavy-fermion materials.

Contribution

It introduces a symmetry-enforced mechanism explaining heavy-fermion physics in d-electron systems, demonstrated in quadruple-perovskite CaCu3Ir4O12.

Findings

Electron hoppings between Cu 3d-orbitals are symmetry-forbidden.

Heavy-fermion behavior arises from hybridization with itinerant bands.

Provides a pathway to design new d-electron heavy-fermion materials.

Abstract

Heavy-fermion materials are mostly rare-earth or actinide intermetallics with very few exceptions in d-electron systems. The physical mechanism for these d-electron heavy fermion systems remains unclear. Here by studying the quadruple-perovskite CaCu3Ir4O12, we propose a symmetry-based mechanism that may enforce heavy-fermion physics in d-electron systems. We show that electron hoppings between neighboring Cu 3d-orbitals are strictly prohibited by the crystal symmetry, so that Cu 3d-electrons can only become delocalized through hybridization with other more itinerant bands, resembling that in typical heavy-fermion rare-earth intermetallics. This provides a useful way to enforce heavy-fermion physics in d-electron systems and may help future design of new heavy-fermion materials.