Origin of the insulating state in the Kitaev candidate Cu$_2$IrO$_3$

Fuente: arXiv
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Main Authors: Li, Ying, Johnson, Roger D., Singh, Yogesh, Coldea, Radu, Valentí, Roser
Format: Preprint
Published: 2024
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_version_ 1866916500923744256
author Li, Ying
Johnson, Roger D.
Singh, Yogesh
Coldea, Radu
Valentí, Roser
author_facet Li, Ying
Johnson, Roger D.
Singh, Yogesh
Coldea, Radu
Valentí, Roser
contents Through a combination of crystal symmetry analysis and density functional theory calculations we unveil a possible microscopic origin of the unexpected insulating behavior reported in the honeycomb Kitaev material Cu$_2$IrO$_3$. Our study suggests that this material hosts an instability towards charge ordering of the Ir ions, with alternating magnetic Ir$^{4+}$ and non-magnetic Ir$^{3+}$ ions arranged on the honeycomb lattice. In this case, the next-nearest-neighbor interactions that couple magnetic Ir$^{4+}$ ions form an enlarged triangular lattice, instead of the expected honeycomb lattice. The magnetic Cu$^{2+}$ ions located at the centre of the iridium honeycomb voids also form a triangular lattice, and additionally contribute to the magnetization of the system. Together, the interpenetrated Ir$^{4+}$ and Cu$^{2+}$ triangular lattices present a novel type of honeycomb Kitaev lattice composed of two types of magnetic ions.
format Preprint
id arxiv_https___arxiv_org_abs_2412_00220
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Origin of the insulating state in the Kitaev candidate Cu$_2$IrO$_3$
Li, Ying
Johnson, Roger D.
Singh, Yogesh
Coldea, Radu
Valentí, Roser
Strongly Correlated Electrons
Through a combination of crystal symmetry analysis and density functional theory calculations we unveil a possible microscopic origin of the unexpected insulating behavior reported in the honeycomb Kitaev material Cu$_2$IrO$_3$. Our study suggests that this material hosts an instability towards charge ordering of the Ir ions, with alternating magnetic Ir$^{4+}$ and non-magnetic Ir$^{3+}$ ions arranged on the honeycomb lattice. In this case, the next-nearest-neighbor interactions that couple magnetic Ir$^{4+}$ ions form an enlarged triangular lattice, instead of the expected honeycomb lattice. The magnetic Cu$^{2+}$ ions located at the centre of the iridium honeycomb voids also form a triangular lattice, and additionally contribute to the magnetization of the system. Together, the interpenetrated Ir$^{4+}$ and Cu$^{2+}$ triangular lattices present a novel type of honeycomb Kitaev lattice composed of two types of magnetic ions.
title Origin of the insulating state in the Kitaev candidate Cu$_2$IrO$_3$
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2412.00220