Frustration induced non-Curie-Weiss paramagnetism in La3Ir3O11: a fractional-valence-state iridate

TL;DR

This study investigates La3Ir3O11, revealing a non-Curie-Weiss paramagnetic state driven by frustration and spin-orbit effects, with potential implications for understanding spin liquid behavior in iridates.

Contribution

The paper combines experimental and theoretical approaches to identify a novel non-Curie-Weiss paramagnetic state in a fractional-valence iridate, suggesting a candidate for a spin liquid.

Findings

No magnetic order observed down to 2 K

Spin-orbit driven Mott insulating behavior confirmed

Evidence of geometrical frustration leading to unusual paramagnetism

Abstract

Experimental and theoretical studies are performed on La3Ir3O11, an iridate hosting a +4.33 fractional valence state for Ir ions and a three-dimensional frustrated structure composed of edge-shared Ir2O10 dimers. These features are expected to enhance inter-site hoppings and reduce magnetic moments of Ir ions. However, a spin-orbit driven Mott insulating transport is observed, which is supported by our first principles calculations. Most importantly, geometrical frustration and competing interactions result in a non-Curie-Weiss paramagnetic ground state, revealing no magnetic order down to 2 K. This unusual state is further demonstrated by a theoretical modeling process, suggesting a possible candidate for the spin liquid state.