Role of dispersion relation effect in topological surface-enhanced Raman scattering

Abstract

Topological surface-enhanced Raman scattering (T-SERS) is a phenomenon in which topological materials change the density of states (DOS) of the substrate through linear dispersion relation to boost photoinduced charge transfer and enhance Raman scattering. Through theoretical and experimental research, we show that the dispersion relation effect in topological materials is the main reason for T-SERS. In theory, the dispersion relation and dimension of the band structure will affect the distribution of DOS near the Fermi surface of substrates, and the change of DOS will lead to the different contribution of charge transfer for SERS. In experiments, the enhancement effect of topological insulators (Bi 2 Se 3 , Sb 2 Te 3 ) and topological semimetal (PtSe 2 ) on the Raman scattering of various molecules are compared. Among these materials, PtSe 2 can achieve Raman enhancement of R6G molecules with the concentration of 10 −9 M. Topological SERS on topological insulator and topological semimetal The dispersion relation of the substrates affects the contribution of charge transfer PtSe 2 films with 3D linear dispersion relation achieve obvious Raman enhancement Hou et al. report that Bi2Se3, Sb2Te3, and PtSe2 films with linear dispersion relation increase the contribution of charge transfer for topological SERS. All of the samples could probe the signals of R6G, CV, MeB, and MB. The detection limit of R6G on PtSe2 films can be as low as 10 −9 M.