Building spin-1/2 antiferromagnetic Heisenberg chains with diaza-nanographenes
- URL: http://arxiv.org/abs/2407.20511v1
- Date: Tue, 30 Jul 2024 02:58:33 GMT
- Title: Building spin-1/2 antiferromagnetic Heisenberg chains with diaza-nanographenes
- Authors: Xiaoshuai Fu, Li Huang, Kun Liu, João C. G. Henriques, Yixuan Gao, Xianghe Han, Hui Chen, Yan Wang, Carlos-Andres Palma, Zhihai Cheng, Xiao Lin, Shixuan Du, Ji Ma, Joaquín Fernández-Rossier, Xinliang Feng, Hong-Jun Gao,
- Abstract summary: Graphene nanostructures with pi-magnetism offer a chemically tunable platform to explore quantum magnetic interactions.
We demonstrate the successful on-surface synthesis of spin-1/2 antiferromagnetic Heisenberg chains with parity-dependent magnetization.
Our findings provide an effective strategy to construct nanographene spin chains and unveil the odd-even effect in their magnetic properties.
- Score: 12.13904791704878
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Understanding and engineering the coupling of spins in nanomaterials is of central importance for designing novel devices. Graphene nanostructures with {\pi}-magnetism offer a chemically tunable platform to explore quantum magnetic interactions. However, realizing spin chains bearing controlled odd-even effects with suitable nanographene systems is challenging. Here, we demonstrate the successful on-surface synthesis of spin-1/2 antiferromagnetic Heisenberg chains with parity-dependent magnetization based on antiaromatic diaza-hexa-peri-hexabenzocoronene (diaza-HBC) units. Using distinct synthetic strategies, two types of spin chains with different terminals were synthesized, both exhibiting a robust odd-even effect on the spin coupling along the chain. Combined investigations using scanning tunneling microscopy, non-contact atomic force microscopy, density functional theory calculations, and quantum spin models confirmed the structures of the diaza-HBC chains and revealed their magnetic properties, which has an S = 1/2 spin per unit through electron donation from the diaza-HBC core to the Au(111) substrate. Gapped excitations were observed in even-numbered chains, while enhanced Kondo resonance emerged in odd-numbered units of odd-numbered chains due to the redistribution of the unpaired spin along the chain. Our findings provide an effective strategy to construct nanographene spin chains and unveil the odd-even effect in their magnetic properties, offering potential applications in nanoscale spintronics.
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