Plasmons dispersion and nonvertical interband transitions in single crystal Bi2Se3 investigated by electron energy-loss spectroscopy
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
87
Journal Issue
8
Date Issued
2013
Author(s)
Abstract
Plasmons dispersion and nonvertical interband transitions in Bi 2Se3 single crystals were investigated by electron energy-loss spectroscopy in conjunction with (scanning) transmission electron microscopy [(S)TEM-EELS]. Both volume plasmons (π plasmon at 7 eV and π + σ plasmon at 17 eV) and surface plasmons (∼5.5 and 10 eV) were demonstrated in STEM-EELS spectra and the corresponding spectral imaging in real space. In further EELS experiments in reciprocal space, the momentum-dependent spectra reveal very different dispersion behavior between π and π + σ plasmons, with π + σ plasmons showing a typical quadratic dependence, whereas the π plasmon exhibited a linear dispersion analogous to what was reported for graphene. Furthermore, a low energy excitation 0.7-1.6 eV was also observed which is attributed to direct nonvertical interband transitions along the ΓF direction. © 2013 American Physical Society.
SDGs
Type
journal article