Publication date: Oct 11, 2021
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 effect, solitons in one-dimensional conducting polymers and Majorana states in topological superconductors. 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 bulk and, remarkably, S = 1/2 edge states at the chain termini, leading to a four-fold degenerate ground state that reflects the underlying symmetry-protected topological order. This record contains data to support the result in a recent publication of ours where we use on-surface synthesis to fabricate one-dimensional spin chains that contain the S = 1 polycyclic aromatic hydrocarbon triangulene as the building block. Using scanning tunneling 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 computation.
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File name | Size | Description |
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ReadMe.yaml
MD5md5:6242eda3d8e18dd69a4141bb2f3e22d3
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73.9 KiB | ReadME file in yaml format detailing the content of the record |
data.tgz
MD5md5:9b3f9cfd90a5b645e522154c0327114e
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59.4 MiB | Compressed tar file containing the experimental data and the gw calculations of the record |
band-and-geo-calculations.aiida
MD5md5:a160ddf10bb8044c2394c3cc8ace49ef
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13.2 GiB | Archive of AiiDA nodes of the bandstructure calculations |
2021.161 (version v1) [This version] | Oct 11, 2021 | DOI10.24435/materialscloud:e8-aq |