Observation of fractional edge excitations in nanographene spin chains
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Título: | Observation of fractional edge excitations in nanographene spin chains |
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Autor/es: | Mishra, Shantanu | Catarina, Gonçalo | Wu, Fupeng | Ortiz-Cano, Ricardo | Jacob, David | Eimre, Kristjan | Ma, Ji | Pignedoli, Carlo A. | Feng, Xinliang | Ruffieux, Pascal | Fernández-Rossier, Joaquín | Fasel, Roman |
Grupo/s de investigación o GITE: | Grupo de Nanofísica |
Centro, Departamento o Servicio: | Universidad de Alicante. Departamento de Física Aplicada |
Palabras clave: | Fractional edge excitations | Nanographene | Spin chains |
Área/s de conocimiento: | Física de la Materia Condensada |
Fecha de publicación: | 13-oct-2021 |
Editor: | Springer Nature |
Cita bibliográfica: | Nature. 2021, 598: 287-292. https://doi.org/10.1038/s41586-021-03842-3 |
Resumen: | Fractionalization is a phenomenon in which strong interactions in a quantum system drive the emergence of excitations with quantum numbers that are absent in the building blocks. Outstanding examples are excitations with charge e/3 in the fractional quantum Hall effect1,2, solitons in one-dimensional conducting polymers3,4 and Majorana states in topological superconductors5. Fractionalization is also predicted to manifest itself in low-dimensional quantum magnets, such as one-dimensional antiferromagnetic S = 1 chains. The fundamental features of this system are gapped excitations in the bulk6 and, remarkably, S = 1/2 edge states at the chain termini7,8,9, leading to a four-fold degenerate ground state that reflects the underlying symmetry-protected topological order10,11. Here, we use on-surface synthesis12 to fabricate one-dimensional spin chains that contain the S = 1 polycyclic aromatic hydrocarbon triangulene as the building block. Using scanning tunnelling microscopy and spectroscopy at 4.5 K, we probe length-dependent magnetic excitations at the atomic scale in both open-ended and cyclic spin chains, and directly observe gapped spin excitations and fractional edge states therein. Exact diagonalization calculations provide conclusive evidence that the spin chains are described by the S = 1 bilinear-biquadratic Hamiltonian in the Haldane symmetry-protected topological phase. Our results open a bottom-up approach to study strongly correlated phases in purely organic materials, with the potential for the realization of measurement-based quantum computation13. |
Patrocinador/es: | This work was supported by the Swiss National Science Foundation (grant numbers 200020-182015 and IZLCZ2-170184), the NCCR MARVEL funded by the Swiss National Science Foundation (grant number 51NF40-182892), the European Union’s Horizon 2020 research and innovation program (grant number 881603, Graphene Flagship Core 3), the Office of Naval Research (N00014-18-1-2708), ERC Consolidator grant (T2DCP, grant number 819698), the German Research Foundation within the Cluster of Excellence Center for Advancing Electronics Dresden (cfaed) and EnhanceNano (grant number 391979941), the Basque Government (grant number IT1249-19), the Generalitat Valenciana (Prometeo2017/139), the Spanish Government (grant number PID2019-109539GB-C41), and the Portuguese FCT (grant number SFRH/BD/138806/2018). Computational support from the Swiss Supercomputing Center (CSCS) under project ID s904 is gratefully acknowledged. |
URI: | http://hdl.handle.net/10045/118696 |
ISSN: | 0028-0836 (Print) | 1476-4687 (Online) |
DOI: | 10.1038/s41586-021-03842-3 |
Idioma: | eng |
Tipo: | info:eu-repo/semantics/article |
Derechos: | © 2021 Springer Nature Limited |
Revisión científica: | si |
Versión del editor: | https://doi.org/10.1038/s41586-021-03842-3 |
Aparece en las colecciones: | Investigaciones financiadas por la UE INV - Grupo de Nanofísica - Artículos de Revistas |
Archivos en este ítem:
Archivo | Descripción | Tamaño | Formato | |
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Mishra_etal_2021_Nature_final.pdf | Versión final (acceso restringido) | 5,69 MB | Adobe PDF | Abrir Solicitar una copia |
Mishra_etal_2021_Nature_preprint.pdf | Preprint (acceso abierto) | 18,51 MB | Adobe PDF | Abrir Vista previa |
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