Content area
Full Text
news & views
temperature. They showed that the plasmon wavevector is indeed tunable by changing the width and periodicity of the grating. Then, by comparing their measurements with theory, they isolated the eect of phonon scattering in the system and demonstrated that the plasmons thus exhibit a dispersion that is consistent with a collective excitation of the two-dimensional Dirac surface-state electrons, rather than with the massive bulk electrons.
Moreover, it has been shown that the spin texture of the Dirac surface statesin topological insulators prevents the backscattering of electrons from non-magnetic defects. Such inherent robustness would make the surface-state electrons more immune to surface quality issues and could result in an enhanced lifetime of the plasmons. Lupi and co-workers show some evidence of this eect, as they found that the plasmon linewidth, a parameter thatis usually sensitive to the lifetime of the
species under study, changed surprisingly little with temperatures ranging from 6to 300K. The insensitivity of these plasmons lifetime with temperature is quite...