Field-induced quantum spin disordered state in spin-1/2 honeycomb magnet Na2Co2TeO6

TL;DR

This study investigates Na2Co2TeO6, a 3d honeycomb magnet, revealing a field-induced quantum disordered state and expanding the Kitaev model to 3d compounds, highlighting the role of spin-orbit coupling.

Contribution

It provides experimental evidence of a field-induced disordered state in a 3d honeycomb magnet, extending the Kitaev model beyond 4d/5d systems.

Findings

Identified a field-induced spin disordered state between 7.5 T and 10.5 T.

Simulated INS spectra to estimate exchange interactions.

Expanded the applicability of the Kitaev model to 3d-based honeycomb magnets.

Abstract

Spin-orbit coupled honeycomb magnets with the Kitaev interaction have received a lot of attention due to their potential of hosting exotic quantum states including quantum spin liquids. Thus far, the most studied Kitaev systems are 4d/5d-based honeycomb magnets. Recent theoretical studies predicted that 3d-based honeycomb magnets, including Na2Co2TeO6 (NCTO), could also be a potential Kitaev system. Here, we have used a combination of heat capacity, magnetization, electron spin resonance measurements alongside inelastic neutron scattering (INS) to study NCTO's quantum magnetism, and we have found a field-induced spin disordered state in an applied magnetic field range of 7.5 T < B (vertical to b-axis) < 10.5 T. The INS spectra were also simulated to tentatively extract the exchange interactions. As a 3d-magnet with a field-induced disordered state on an effective spin-1/2 honeycomb lattice, NCTO expands the Kitaev model to 3d compounds, promoting further interests on the spin-orbital effect in quantum magnets.