CaCo$_2$TeO$_6$: A topochemically prepared 3$d^7$ honeycomb Kitaev magnet

TL;DR

This study investigates CaCo$_2$TeO$_6$, a topochemically synthesized honeycomb magnet, revealing its potential as a Kitaev quantum spin liquid candidate due to its unique magnetic properties and structural features.

Contribution

It introduces CaCo$_2$TeO$_6$ as a new Kitaev candidate synthesized via topochemical ion exchange, demonstrating its magnetic behavior and reduced trigonal distortion.

Findings

CaCo$_2$TeO$_6$ orders antiferromagnetically at 13 K.

Magnetic order is suppressed by a 4 T field.

Reduced trigonal distortion influences magnetic interactions.

Abstract

We report the magnetic properties of CaCo$_2$TeO$_6$ as a Kitaev candidate. CaCo$_2$TeO$_6$ was synthesized through a topochemical process, wherein all Na$^+$ ions in Na$_2$Co$_2$TeO$_6$ were replaced with half the amount of Ca$^{2+}$ ions. This substitution brings the CoO$_6$ octahedra closer to an approximate cubic symmetry. CaCo$_2$TeO$_6$ exhibits antiferromagnetic ordering at $T_N \sim 13$ K, which is lower than $\sim$ 27 K observed for Na$_2$Co$_2$TeO$_6$. Notably, its magnetic order is suppressed in a relatively low magnetic field of approximately 4 T, indicating that non-Kitaev interactions can be restrained by reducing trigonal distortion. Our findings highlight the potential of CaCo$_2$TeO$_6$ as a viable platform for exploring Kitaev quantum spin liquids and pave the way for a deeper understanding of the fundamental mechanisms in Kitaev physics.