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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Collective excitations in spin-polarized bilayer graphene.
Nguyen Van Men1,2, Nguyen Quoc Khanh2,3, Dong Thi Kim Phuong1,2
1University of An Giang-VNUHCM, 18-Ung Van Khiem Street, Long Xuyen, An Giang, Vietnam.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|November 30, 2020
Summary
Spin polarization has minimal impact on long-wavelength plasmon frequency in bilayer graphene (BLG). However, it strongly influences damping rates and critical wave vectors, offering experimental insights into spin polarization.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Bilayer graphene (BLG) exhibits unique electronic properties.
- Plasma oscillations are fundamental excitations in electron systems.
- Spin polarization can significantly alter material characteristics.
Purpose of the Study:
- To investigate the influence of spin polarization on plasmon frequency and damping rate in BLG.
- To derive analytical expressions for plasmon properties under spin polarization.
- To explore the potential for experimental determination of spin polarization degree.
Main Methods:
- Utilizing the long-wavelength approximation for the dynamical dielectric function.
- Performing analytical calculations for plasmon frequency.
- Conducting numerical simulations to analyze plasmon frequency and damping rate dependence on wave vector and spin polarization.
- Identifying the critical wave vector for plasmon dispersion.
Main Results:
- Spin polarization (P) has a negligible effect on long-wavelength plasmon frequency.
- Plasmon frequency shows noticeable (slight) increases (decreases) with P in large (small) wave-vector regions.
- Damping rate (γ) and its wave-vector dependence are strongly influenced by P.
- Increased carrier density significantly reduces both plasmon frequency and damping rate, irrespective of spin polarization.
- The critical wave vector decreases with increasing P.
Conclusions:
- Spin polarization's impact on BLG plasmons is wave-vector dependent.
- The critical wave vector serves as a measurable indicator of spin polarization degree in BLG.
- These findings offer insights into the manipulation and detection of spin properties in 2D materials.
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