More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions

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Auteurs principaux: Bhattacharyya, Pritam, Bogdanov, Nikolay A., Hozoi, Liviu
Format: Preprint
Publié: 2025
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author Bhattacharyya, Pritam
Bogdanov, Nikolay A.
Hozoi, Liviu
author_facet Bhattacharyya, Pritam
Bogdanov, Nikolay A.
Hozoi, Liviu
contents A magnet is a collection of magnetic moments. How those interact is determined by what lies in between. In transition-metal and rare-earth magnetic compounds, the configuration of the ligands around each magnetic center and the connectivity of the ligand cages are therefore pivotal -- for example, the mutual interaction of magnetic species connected through one single ligand is qualitatively different from the case of two bridging anions. Two bridging ligands are encountered in Kitaev magnets. The latter represent one of the revelations of the 21st century in magnetism research: they feature highly anisotropic intersite couplings with seemingly counterintuitive directional dependence for adjacent pairs of magnetic sites and unique quantum spin-liquid ground states that can be described analytically. Current scenarios for the occurrence of pair-dependent magnetic interactions as proposed by Kitaev rely on $indirect$ exchange mechanisms based on intersite electron hopping. Analyzing the wavefunctions of Kitaev magnetic bonds at both single- and multi-configuration levels, we find however that $direct$, Coulomb exchange may be at least as important, in 5$d$ and 4$d$ $t_{2g}^5$, 3$d$ $t_{2g}^5e_g^2$, and even rare-earth 4$f^1$ Kitaev-Heisenberg magnets. Our study provides concept clarification in Kitaev magnetism research and the essential reference points for reliable computational investigation of how novel magnetic ground states can be engineered in Kitaev, Kitaev-Heisenberg, and Heisenberg edge-sharing systems.
format Preprint
id arxiv_https___arxiv_org_abs_2510_04149
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions
Bhattacharyya, Pritam
Bogdanov, Nikolay A.
Hozoi, Liviu
Strongly Correlated Electrons
A magnet is a collection of magnetic moments. How those interact is determined by what lies in between. In transition-metal and rare-earth magnetic compounds, the configuration of the ligands around each magnetic center and the connectivity of the ligand cages are therefore pivotal -- for example, the mutual interaction of magnetic species connected through one single ligand is qualitatively different from the case of two bridging anions. Two bridging ligands are encountered in Kitaev magnets. The latter represent one of the revelations of the 21st century in magnetism research: they feature highly anisotropic intersite couplings with seemingly counterintuitive directional dependence for adjacent pairs of magnetic sites and unique quantum spin-liquid ground states that can be described analytically. Current scenarios for the occurrence of pair-dependent magnetic interactions as proposed by Kitaev rely on $indirect$ exchange mechanisms based on intersite electron hopping. Analyzing the wavefunctions of Kitaev magnetic bonds at both single- and multi-configuration levels, we find however that $direct$, Coulomb exchange may be at least as important, in 5$d$ and 4$d$ $t_{2g}^5$, 3$d$ $t_{2g}^5e_g^2$, and even rare-earth 4$f^1$ Kitaev-Heisenberg magnets. Our study provides concept clarification in Kitaev magnetism research and the essential reference points for reliable computational investigation of how novel magnetic ground states can be engineered in Kitaev, Kitaev-Heisenberg, and Heisenberg edge-sharing systems.
title More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2510.04149