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| Format: | Preprint |
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2024
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| Online-Zugang: | https://arxiv.org/abs/2410.15327 |
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| _version_ | 1866914980920557568 |
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| author | Ji, Liang-Wen Wu, Si-Qi Li, Bai-Zhuo Yang, Wu-Zhang Song, Shi-Jie Liu, Yi Li, Jing Ren, Zhi Cao, Guang-Han |
| author_facet | Ji, Liang-Wen Wu, Si-Qi Li, Bai-Zhuo Yang, Wu-Zhang Song, Shi-Jie Liu, Yi Li, Jing Ren, Zhi Cao, Guang-Han |
| contents | The antiferromagnetism in transition metal compounds is mostly mediated by the bridging anions through a so-called superexchange mechanism. However, in materials like normal spinels $AB_2X_4$ with local moments only at the $A$ site, such an anion-mediated superexchange needs to be modified. Here we report a new spinel compound Co$_{1+x}$Ir$_{2-x}$S$_4$ ($x$ = 0.3). The physical property measurements strongly suggest an antiferromagnetic-like transition at 292 K in the Co($A$) diamond sublattice. The first-principle calculations reveal that the nearest-neighbor Co($A$) spins align antiferromagnetically with an ordered magnetic moment of 1.67 $μ_\mathrm{B}$, smaller than the expected $S = 3/2$ for Co$^{2+}$. In the antiferromagnetic state, there exists an inter-cation charge-transfer gap between the non-bonding Ir-$t_\mathrm{2g}$ orbitals at the valence band maximum and the Co-S antibonding molecular orbitals at the conduction band minimum. The small charge transfer energy significantly enhances the virtual hopping between these two states, facilitating a robust long-range superexchange interaction between two neighboring CoS$_4$ complexes, which accounts for the high Néel temperature in Co$_{1+x}$Ir$_{2-x}$S$_4$. This inter-cation charge transfer mediated magnetic interaction expands the traditional superexchange theory, which could be applicable in complex magnetic materials with multiple cations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_15327 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Inter-Cation Charge Transfer Mediated Antiferromagnetism in Co$_{1+x}$Ir$_{2-x}$S$_4$ Ji, Liang-Wen Wu, Si-Qi Li, Bai-Zhuo Yang, Wu-Zhang Song, Shi-Jie Liu, Yi Li, Jing Ren, Zhi Cao, Guang-Han Materials Science Strongly Correlated Electrons The antiferromagnetism in transition metal compounds is mostly mediated by the bridging anions through a so-called superexchange mechanism. However, in materials like normal spinels $AB_2X_4$ with local moments only at the $A$ site, such an anion-mediated superexchange needs to be modified. Here we report a new spinel compound Co$_{1+x}$Ir$_{2-x}$S$_4$ ($x$ = 0.3). The physical property measurements strongly suggest an antiferromagnetic-like transition at 292 K in the Co($A$) diamond sublattice. The first-principle calculations reveal that the nearest-neighbor Co($A$) spins align antiferromagnetically with an ordered magnetic moment of 1.67 $μ_\mathrm{B}$, smaller than the expected $S = 3/2$ for Co$^{2+}$. In the antiferromagnetic state, there exists an inter-cation charge-transfer gap between the non-bonding Ir-$t_\mathrm{2g}$ orbitals at the valence band maximum and the Co-S antibonding molecular orbitals at the conduction band minimum. The small charge transfer energy significantly enhances the virtual hopping between these two states, facilitating a robust long-range superexchange interaction between two neighboring CoS$_4$ complexes, which accounts for the high Néel temperature in Co$_{1+x}$Ir$_{2-x}$S$_4$. This inter-cation charge transfer mediated magnetic interaction expands the traditional superexchange theory, which could be applicable in complex magnetic materials with multiple cations. |
| title | Inter-Cation Charge Transfer Mediated Antiferromagnetism in Co$_{1+x}$Ir$_{2-x}$S$_4$ |
| topic | Materials Science Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2410.15327 |