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Updated: Mar 23, 2026
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Published on: June 28, 2018
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Fano q-reversal in topological insulator Bi2Se3
S V Dordevic1, G M Foster1, M S Wolf1
1Department of Physics, The University of Akron, Akron, OH 44325, USA.
Summary
We investigated electron-phonon coupling in topological insulator Bi2Se3. A magnetic field reversed the Fano asymmetry parameter (q) of a phonon mode, a novel observation in magneto-optics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Optics
Background:
- Topological insulators (TIs) like Bi2Se3 exhibit unique electronic properties.
- Electron-phonon coupling is crucial for understanding TI behavior but remains debated.
- Magneto-optical spectroscopy is a powerful tool for probing electron dynamics.
Purpose of the Study:
- To investigate the magneto-optical response of Bi2Se3.
- To clarify the role of electron-phonon coupling in TIs.
- To explore magnetic-field effects on phonon modes.
Main Methods:
- Magneto-optical spectroscopy was employed to measure reflectance.
- Infrared spectroscopy probed phonon modes.
- Fano formalism was used to analyze spectral line-shapes.
Main Results:
- Strong electron-phonon coupling was observed in Bi2Se3 via infrared reflectance.
- A 60 cm⁻¹ phonon mode exhibited asymmetric line-shape due to coupling.
- The Fano asymmetry parameter (q) reversed sign when cyclotron resonance matched the phonon frequency.
Conclusions:
- The study provides evidence for significant electron-phonon coupling in Bi2Se3.
- A novel magnetic-field-driven reversal of the Fano asymmetry parameter (q) was demonstrated.
- This finding offers new insights into magneto-optical phenomena in topological insulators.
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