English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present an analytical study of the exchange interactions betweenpseudospin one-half $d^{5}$ ions in honeycomb lattices with edge-sharedoctahedra. Various exchange channels involving Hubbard U, charge-transferexcitations, and cyclic exchange are considered. Hoppings within $t_{2g}$orbitals as well as between $t_{2g}$ and $e_g$ orbitals are included. Specialattention is paid to the trigonal crystal field $\Delta$ effects on theexchange parameters. The obtained exchange Hamiltonian is dominated byferromagnetic Kitaev interaction K within a wide range of $\Delta$. It is foundthat a parameter region close to the charge-transfer insulator regime and witha small $\Delta$ is most promising to realize the Kitaev spin liquid phase. Tworepresentative honeycomb materials Na$_2$IrO$_3$ and $\alpha$-RuCl$_3$ arediscussed based on our theory. We have found that both materials share dominantferromagnetic K and positive non-diagonal $\Gamma$ values. However, theirHeisenberg J terms have opposite signs: AFM J>0 in Na$_2$IrO$_3$ and FM J<0 in$\alpha$-RuCl$_3$. This brings different magnetic fluctuations and results intheir different magnetization behaviors and spin excitation spectra. Proximityto FM state due to the large FM J is emphasized in $\alpha$-RuCl$_3$. Thedifferences between the exchange couplings of these two materials originatefrom the opposite $\Delta$ values, indicating that the crystal field can serveas an efficient control parameter to tune the magnetic properties of $d^{5}$spin-orbit Mott insulators.

Exchange interactions in $d^{5}$ Kitaev materials: From Na$_2$IrO$_3$ to $\alpha$-RuCl$_3$