Influence of electronic band topology on Raman spectroscopy

Raman spectroscopy is a valuable characterization tool for two dimensional (2D) materials. Although some of these materials are topological, the signatures of electronic band topology in Raman scattering have remained elusive and largely unexplored. In this talk, I will provide two theoretical examples on how electronic band topology might influence Raman scattering in 2D Dirac materials. First, I will present a way to detect the recently predicted phonon helicity [1] through circularly polarized Raman scattering [2] in 2D Dirac materials with time-reversal symmetry. This phonon helicity results (at least in part) from the electronic valley Chern number. Second, I will discuss a fingerprint of the electronic Chern number in the Raman tensor elements of 2D Dirac materials without time-reversal symmetry.

[1] L.-H. Hu, J. Yu., I. Garate and C.-X. Liu, Phys. Rev. Lett. 127, 125901 (2021).

[2] S. Parlak, S. Ghosh and I. Garate, Phys. Rev. B 107, 104308 (2023).