Anharmonic Bloch oscillation of electrons in biased superlattices
K. A. Ivanov+*, A. G. Petrov×, M. A. Kaliteevski+*×, A. J. Gallant°
+St. Petersburg Academic University, 194021 St. Petersburg, Russia
*St. Petersburg National Research University of Information Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
×Ioffe Physico-Technical Institute of the RAS, 194021 St. Petersburg, Russia
°School of Engineering and Computing Sciences, Durham University, South Road, DH1 3LE Durham, UK
Abstract
The oscillatory motion of electrons in a periodic
potential under a constant applied electric
field, known as Bloch Oscillations (BO), is one of the most
striking and intriguing quantum
effects and was predicted more than eighty years ago.
Oscillating electrons emit
electromagnetic radiation and here we consider this BO
effect for emission in the THz region.
To date, it has been assumed that the Bloch oscillation
of an electron is an harmonic
oscillation, therefore with radiation emitted at the single
Bloch frequency. We analyze
scenarios when Bloch oscillations can be accompanied by the
emission of radiation not only at
the Bloch frequency but also with double and triple Bloch
frequencies. The first scenario
means that electrons could jump over neighboring Stark
states. The second scenario of
anharmonic emission is coupled to an opening of the minigap
in the miniband.