Detuning the Honeycomb of the {\alpha}-RuCl3 Kitaev lattice: A case of Cr3+ dopant

TL;DR

This study explores how doping { extalpha}-RuCl3 with Cr3+ ions affects its honeycomb lattice and magnetic properties, revealing structural preservation but suppression of Kitaev physics due to dominant Cr3+ magnetism.

Contribution

It demonstrates successful synthesis of Cr-doped { extalpha}-RuCl3 crystals with preserved lattice structure and provides insights into how Cr doping influences magnetic interactions and Kitaev physics.

Findings

Cr doping maintains honeycomb lattice structure

Stacking disorder increases with Cr doping

Kitaev physics is suppressed by Cr3+ magnetism

Abstract

Fine-tuning chemistry by doping with transition metals enables new perspectives for exploring Kitaev physics on a two-dimensional (2D) honeycomb lattice of {\alpha}-RuCl3, which is promising in the field of quantum information protection and quantum computation. The key parameters to vary by doping are both Heisenberg and Kitaev components of the nearest-neighbor exchange interaction between the Jeff = 1/2 Ru3+ spins, depending strongly on the peculiarities of the crystal structure. Here, we successfully grew single crystals of the solid solution series Ru1-xCrxCl3 with Cr3+ ions coupled to the Ru3+ Kitaev host using chemical vapour transport reaction. The Cr3+ substitution preserves the honeycomb type lattice of {\alpha}-RuCl3 with mixed occupancy of Ru/Cr sites, no hints on cationic order within the layers were found by single crystal X-ray diffraction and transmission electron microscopy investigations. In contrast to the high quality single crystals of {\alpha}-RuCl3 with ABAB ordered layers, the ternary compounds demonstrate a significant stacking disorder along the c-axis direction evidenced by X-ray diffraction and high resolution scanning transmission electron microscopy (HR-STEM). Raman spectra of substituted samples are in line with a symmetry conservation of the parent lattice upon chromium doping. At the same time, magnetic susceptibility data indicate that the Kitaev physics of {\alpha}-RuCl3 is increasingly repressed by the dominant spin-only driven magnetism of Cr3+ in Ru1-xCrxCl3.