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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2402.13590 |
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| _version_ | 1866917596993945600 |
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| author | Zhao, Chenxiao Catarina, Gonçalo Zhang, Jin-Jiang Henriques, João C. G. Yang, Lin Ma, Ji Feng, Xinliang Gröning, Oliver Ruffieux, Pascal Fernández-Rossier, Joaquín Fasel, Roman |
| author_facet | Zhao, Chenxiao Catarina, Gonçalo Zhang, Jin-Jiang Henriques, João C. G. Yang, Lin Ma, Ji Feng, Xinliang Gröning, Oliver Ruffieux, Pascal Fernández-Rossier, Joaquín Fasel, Roman |
| contents | Unlocking the potential of topological order within many-body spin systems has long been a central pursuit in the realm of quantum materials. Despite extensive efforts, the quest for a versatile platform enabling site-selective spin manipulation, essential for tuning and probing diverse topological phases, has persisted. Here, we utilize on-surface synthesis to construct spin-1/2 alternating-exchange Heisenberg (AH) chains[1] with antiferromagnetic couplings $J_1$ and $J_2$ by covalently linking Clar's goblets -- nanographenes each hosting two antiferromagnetically-coupled unpaired electrons[2]. Utilizing scanning tunneling microscopy, we exert atomic-scale control over the spin chain lengths, parities and exchange-coupling terminations, and probe their magnetic response by means of inelastic tunneling spectroscopy. Our investigation confirms the gapped nature of bulk excitations in the chains, known as triplons[3]. Besides, the triplon dispersion relation is successfully extracted from the spatial variation of tunneling spectral amplitudes. Furthermore, depending on the parity and termination of chains, we observe varying numbers of in-gap $S=1/2$ edge spins, enabling the determination of the degeneracy of distinct topological ground states in the thermodynamic limit-either 1, 2, or 4. By monitoring interactions between these edge spins, we identify the exponential decay of spin correlations. Our experimental findings, corroborated by theoretical calculations, present a phase-controlled many-body platform, opening promising avenues toward the development of spin-based quantum devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_13590 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Tunable topological phases in nanographene-based spin-1/2 alternating-exchange Heisenberg chains Zhao, Chenxiao Catarina, Gonçalo Zhang, Jin-Jiang Henriques, João C. G. Yang, Lin Ma, Ji Feng, Xinliang Gröning, Oliver Ruffieux, Pascal Fernández-Rossier, Joaquín Fasel, Roman Materials Science Mesoscale and Nanoscale Physics Strongly Correlated Electrons Chemical Physics Quantum Physics Unlocking the potential of topological order within many-body spin systems has long been a central pursuit in the realm of quantum materials. Despite extensive efforts, the quest for a versatile platform enabling site-selective spin manipulation, essential for tuning and probing diverse topological phases, has persisted. Here, we utilize on-surface synthesis to construct spin-1/2 alternating-exchange Heisenberg (AH) chains[1] with antiferromagnetic couplings $J_1$ and $J_2$ by covalently linking Clar's goblets -- nanographenes each hosting two antiferromagnetically-coupled unpaired electrons[2]. Utilizing scanning tunneling microscopy, we exert atomic-scale control over the spin chain lengths, parities and exchange-coupling terminations, and probe their magnetic response by means of inelastic tunneling spectroscopy. Our investigation confirms the gapped nature of bulk excitations in the chains, known as triplons[3]. Besides, the triplon dispersion relation is successfully extracted from the spatial variation of tunneling spectral amplitudes. Furthermore, depending on the parity and termination of chains, we observe varying numbers of in-gap $S=1/2$ edge spins, enabling the determination of the degeneracy of distinct topological ground states in the thermodynamic limit-either 1, 2, or 4. By monitoring interactions between these edge spins, we identify the exponential decay of spin correlations. Our experimental findings, corroborated by theoretical calculations, present a phase-controlled many-body platform, opening promising avenues toward the development of spin-based quantum devices. |
| title | Tunable topological phases in nanographene-based spin-1/2 alternating-exchange Heisenberg chains |
| topic | Materials Science Mesoscale and Nanoscale Physics Strongly Correlated Electrons Chemical Physics Quantum Physics |
| url | https://arxiv.org/abs/2402.13590 |