SmI3: 4f5 honeycomb magnet with spin-orbital entangled {\Gamma}7 Kramers doublet

TL;DR

This study investigates the magnetic properties of SmI3, a 4f honeycomb magnet with a spin-orbit entangled {Gamma}7 Kramers doublet ground state, revealing antiferromagnetic correlations without long-range order.

Contribution

It provides the first detailed characterization of SmI3's magnetic behavior and its potential relation to Kitaev physics in 4f-electron systems.

Findings

Identified {3Gamma}7 Kramers doublet ground state stabilized by spin-orbit coupling.

Detected antiferromagnetic correlations without long-range magnetic order.

Observed anomalies in magnetization curves near saturation.

Abstract

We report magnetic properties of a 4f-honeycomb iodide SmI3 made up of edge-shared network of SmI6 octahedra. High temperature magnetic susceptibility indicates {\Gamma}7 Kramers doublet ground state of Sm3+ (4f5) ions stabilized by the spin-orbit coupling and octahedral crystal electric field, which interact with Sm-I-Sm bond angle nearly 90 degree. Magnetization measurements down to 0.1 K detected antiferromagnetic correlations and an anomaly in the magnetization curve before saturation without a sign of long-range order. Relevance between SmI3 and the antiferromagnetic Kitaev material proposed in the 4f-electron system is discussed.