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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Ultra-long-range spin coupling in graphene revealed by atomically resolved spin excitations.
Beatriz Viña-Bausá1, António Tavares Costa2,3, Joao Henriques2,4
1Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain. beatriz.vina@uam.es.
Nature Communications
|May 19, 2026
Summary
Researchers achieved unprecedented long-range magnetic exchange interactions between spins-½ using hydrogen atoms on graphene. These tunable quantum interactions, exceeding 10 nm, are crucial for quantum computing and simulation advancements.
Area of Science:
- Quantum physics
- Condensed matter physics
- Materials science
Background:
- Magnetic interactions between localized spins (spin-½) are fundamental to quantum magnetism, quantum computing, and quantum simulation.
- The range and strength of these interactions are critical performance metrics for these applications.
Purpose of the Study:
- To investigate and characterize the exchange interactions between pairs of spins-½ introduced by hydrogen atoms chemisorbed on graphene.
- To explore the tunability of these interactions based on atomic arrangement and their potential for quantum technologies.
Main Methods:
- Utilizing scanning tunneling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS) to probe spin interactions.
- Employing large-scale mean-field Hubbard calculations to support experimental findings.
- Performing atomic manipulation to create and study spin trimers.
Main Results:
- Demonstrated exchange couplings of 3 meV at distances exceeding 10 nm, a significant advancement in interaction range.
- Observed both ferromagnetic and antiferromagnetic couplings, controllable by the relative sublattice arrangement of hydrogen atoms.
- Successfully mapped spin excitation amplitudes in real space with atomic resolution.
- Revealed collective spin excitations in spin trimers when pairwise exchange couplings were comparable.
Conclusions:
- Chemisorbed hydrogen atoms on graphene provide a novel platform for achieving long-range, tunable magnetic exchange interactions.
- The demonstrated control and range of interactions open new avenues for building scalable quantum processors and simulators.
- Atomic-level characterization and manipulation capabilities are key to understanding and engineering complex spin systems.
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