Plasmonic Effect on the Magneto-Optical Property of Monolayer WS2 Studied by Polarized-Raman Spectroscopy

In recent years, the magneto-optical properties of two-dimensional transition metal disulfides have attracted more and more attention due to their further device applications in spintronics and valleytronics. However, to our knowledge, the plasmonic effect on the magneto-optical properties of WS2 has not been studied. In this work, monolayer WS2 transferred on SiO2/Si substrate and Au film were investigated respectively using polarized-Raman spectroscopy at 4 K under different magnetic fields. Prominent magnetic field–induced variations in the Raman intensities of WS2 samples were observed, which also exhibited significant differences in the spectral evolution versus magnetic field. The resonance magnetic field was 5 T and 5.5 T for the WS2 on SiO2/Si substrate and Au film, respectively. Remarkably, the magneto-optical Raman intensities of A1′ and 2LA(M) modes for WS2 on Au film were reduced to approximately 60% compared with that of WS2 on SiO2/Si. These results suggest that the plasmonic effect–induced charge transfer plays an important role in the magneto-optical Raman effect of WS2.

Identification of Vibrational Modes in BaSi2 Epitaxial Films by Infrared and Raman Spectroscopy

Infrared (IR) absorption and polarized Raman spectra were measured in BaSi2 epitaxial films to investigate the vibrational modes and the symmetry of Si4 cluster in BaSi2. By an analysis based on Raman and/or IR activity in the spectra, the symmetry of Si4 cluster was determined as Th-symmetry and the observed Raman lines and IR peaks were assigned to Ag, Eg, Fg, and Fu, respectively. In the three Raman lines of Fg-mode, one LO phonon line and two TO phonon lines were classified by the depolarization ratio of polarized Raman intensities.

Plasmon-driven surface catalytic reaction of 4-ethynylaniline in a liquid environment

The mechanism of Ag NP induced dimerization of PEAN was investigated by using SERS spectra. A very interesting phenomenon was discovered, that is where the relative Raman intensities of b2 modes increased either with increasing incident laser power or exposure time.