Li$_2$RhO$_3$: A spin-glassy relativistic Mott insulator

TL;DR

Li$_2$RhO$_3$ is a spin-glassy relativistic Mott insulator with no long-range magnetic order, exhibiting spin-glass behavior and characterized by electronic correlation and spin-orbit coupling effects.

Contribution

This study provides the first systematic investigation of Li$_2$RhO$_3$, revealing its spin-glassy state and relativistic Mott insulating nature driven by electronic correlation and SOC.

Findings

Semiconducting with a 78 meV band gap

No long-range magnetic order down to 0.5 K

Exhibits spin-glass behavior below 6 K

Abstract

Motivated by the rich interplay among electronic correlation, spin-orbit coupling (SOC), crystal-field splitting, and geometric frustrations in the honeycomb-like lattice, we systematically investigated the electronic and magnetic properties of Li$_2$RhO$_3$. The material is semiconducting with a narrow band gap of $\Delta\sim$78 meV, and its temperature dependence of resistivity conforms to 3D variable range hopping mechanism. No long-range magnetic ordering was found down to 0.5 K, due to the geometric frustrations. Instead, single atomic spin-glass behavior below the spin-freezing temperature ($\sim$6 K) was observed and its spin dynamics obeys the universal critical slowing down scaling law. First principle calculations suggested it to be a relativistic Mott insulator mediated by both electronic correlation and SOC. With moderate strength of electronic correlation and SOC, our results shed new light to the research of Heisenberg-Kitaev model in realistic materials.