Plasmons of topological crystalline insulator SnTe with nanostructured patterns

Using the finite-difference time-domain method and density functional theory, we theoretically investigate the plasmons of topological crystalline insulator (TCI) SnTe with nanostructured patterns. Due to the fact that the topological material has an insulating bulk surrounded by topologically protected metallic surfaces, the TCI nanogratings are uniquely described by the core-shell-like model. In contrast to the plasmons of metallic nanoparticles usually found in visible spectra, four plasmon resonances excited on the TCI SnTe nanogratings are numerically observed in the visible-near-infrared (vis-NIR) spectral region, which is in agreement with the theoretical analyses. Furthermore, periodic shifts of resonance wavelengths are achieved with the variation of grating heights. The facile control of the plasmons of TCI nanopatterns in the vis-NIR spectral region may have potential applications in biomedicine, plasmonic nanodevices, and integrated optoelectronic circuits.