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All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
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Determining Energy Dispersion of Spin Excitations with Scanning Tunneling Spectroscopy
J C G Henriques1,2, Chenxiao Zhao3, G Catarina3
1International Iberian Nanotechnology Laboratory (INL), Avenida Mestre José Veiga, 4715-330 Braga, Portugal.
Physical Review Letters
|September 15, 2025
Summary
Scanning tunneling microscopy with inelastic electron tunneling spectroscopy (STM-IETS) can reveal spin excitation dispersion relations in finite-size spin chains by analyzing standing wave formation. However, it cannot resolve spinon excitations in Heisenberg spin-1/2 chains.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Conventional methods for measuring spin excitation dispersion relations rely on bulk samples and well-defined momentum probes.
- Finite-size spin chains lack translation symmetry, precluding well-defined momentum measurements.
- Inelastic electron tunneling spectroscopy (IETS) with a scanning tunneling microscope (STM) offers a local probe for spin excitations in such systems.
Purpose of the Study:
- To determine the conditions under which STM-IETS spectra can be Fourier-transformed to yield dispersion relations in finite-size spin chains.
- To investigate the relationship between standing wave formation of spin excitations and the success of STM-IETS for dispersion measurements.
- To compare theoretical predictions with experimental data on nanographene chains.
Main Methods:
- Theoretical analysis of STM-IETS spectra for finite-size spin chains.
- Fourier transformation of simulated STM-IETS data.
- Comparison of theoretical predictions with experimental measurements on nanographene chains.
Main Results:
- STM-IETS spectra can be Fourier-transformed to yield dispersion relations when spin excitations form standing waves.
- STM-IETS successfully reveals the energy dispersion of magnons in ferromagnets and triplons in valence bond crystals.
- STM-IETS cannot resolve the spinon excitations in Heisenberg spin-1/2 chains.
Conclusions:
- STM-IETS is a viable technique for measuring spin excitation dispersion relations in certain finite-size systems, particularly when standing waves are present.
- The limitations of STM-IETS in resolving spinon excitations highlight the unique nature of these quantum phenomena.
- Experimental validation on nanographene chains supports the theoretical framework for STM-IETS analysis of spin excitations.
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