Raman response of topologically protected surface states in sub‐micrometric Pb_0.77Sn_0.23Se flakes

Abstract

The Raman spectra of the topological crystalline insulator Pb 0.77 Sn 0.23 Se flakes of thickness below 150 nm show the presence of plasma enhanced phonons related to topologically protected surface electronic states. The Fröhlich interaction between the topologically protected surface Dirac electrons and the phonons activates the forbidden phonons near the center of the Brillouin zone. An overtone is observed at a higher wavenumber, with a resonant response with temperature, related to an enhancement of the long-range coupling between the topologically protected surface electrons and phonons.

Thermoelectric and Structural Properties of Sputtered AZO Thin Films with Varying Al Doping Ratios

“…The extracted parameters are summarized in Table 2. Raman spectroscopy provides an extremely versatile, contactless tool for the quantitative investigation of advanced functional materials, ranging from bulky materials [40] to nanostructures and low-dimensional systems, including nanotubes [41], 2D materials [42], and topological materials [43]. Figure 5 presents the results of the Raman analysis carried out on the AZO thin films.…”