Photogalvanic effects in topological insulators
S. N. Artemenko, V. O. Kaladzhyan
Kotel'nikov Institute of Radio-engineering and Electronics of RAS, 125009 Moscow, Russia
Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
Abstract
We discuss optical absorption in topological insulators and study
possible photoelectric effects theoretically. We found that absorption of
circularly polarized electromagnetic waves in two-dimensional topological
insulators results in electric current in the conducting 1D edge channels,
the direction of the current being determined by the light polarization. We
suggest two ways of inducing such a current: due to magnetic dipole electron
transitions stimulated by irradiation of frequency below the bulk energy
gap, and due to electric dipole transitions in the bulk at frequencies larger
than the energy gap with subsequent capture of the photogenerated carriers on
conducting edge states.