Investigation of Electron-Phonon Coupling in Epitaxial Silicene by In-situ Raman Spectroscopy

TL;DR

This study uses in-situ Raman spectroscopy to explore how electron-phonon coupling in silicene on Ag(111) is affected by strain and doping, revealing insights into its unique electronic properties.

Contribution

It demonstrates the modulation of electron-phonon coupling in silicene due to strain and doping, and identifies phonon modes related to Dirac fermion interactions.

Findings

EPC is significantly modulated by tensile strain and charge doping.

Special phonon modes associated with 2D electron gas scattering were identified.

Raman spectroscopy provides a direct method to study Dirac fermion interactions.

Abstract

In this letter, we report that the special coupling between Dirac fermion and lattice vibrations, in other words, electron-phonon coupling (EPC), in silicene layers on Ag(111) surface was probed by an in-situ Raman spectroscopy. We find the EPC is significantly modulated due to tensile strain, which results from the lattice mismatch between silicene and the substrate, and the charge doping from the substrate. The special phonon modes corresponding to two-dimensional electron gas scattering at edge sites in the silicene were identified. Detecting relationship between EPC and Dirac fermion through the Raman scattering will provide a direct route to investigate the exotic property in buckled two-dimensional honeycomb materials.