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Tunable topological phases in nanographene-based spin-1/2 alternating-exchange Heisenberg chains
Chenxiao Zhao1, Gonçalo Catarina1,2, Jin-Jiang Zhang3,4
1Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Nature Nanotechnology
|October 29, 2024
Summary
Researchers created tunable spin chains using on-surface synthesis. This platform allows atomic-scale control over magnetic properties, enabling the study of topological phases and paving the way for quantum devices.
Area of Science:
- Quantum Materials
- Condensed Matter Physics
- Nanotechnology
Background:
- Topological order in many-body spin systems is crucial for quantum materials.
- A versatile platform for site-selective spin manipulation is needed to explore topological phases.
- Previous methods lacked precise control over spin chain properties.
Purpose of the Study:
- To develop a platform for on-surface synthesis of spin-1/2 alternating-exchange Heisenberg chains.
- To achieve atomic-scale control over chain length, parity, and termination.
- To probe the magnetic response and topological properties of these engineered spin chains.
Main Methods:
- On-surface synthesis of nanographene (Clar's goblets) linked into spin chains.
- Scanning tunneling microscopy (STM) for atomic-scale manipulation and control.
- Inelastic tunneling spectroscopy (ITS) to probe magnetic excitations and correlations.
Main Results:
- Confirmed gapped bulk excitations (triplons) with extracted dispersion relations.
- Observed varying numbers of in-gap spin-1/2 edge excitations dependent on chain parity and termination.
- Identified exponential decay of spin correlations by monitoring edge spin interactions.
Conclusions:
- Demonstrated a phase-controlled many-body platform using engineered spin chains.
- Showcased atomic-scale control over topological properties in spin systems.
- Opened new avenues for developing spin-based quantum devices and exploring topological quantum matter.
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