Two‐Phonon Resonance Raman Scattering and Quantum Interference Effects in Polar Semiconductors in High Magnetic Fields

Abstract

AbstractThe EHP contribution to the two‐phonon resonance Raman scattering (RRS) cross‐section is calculated for a polar semiconductor located in a high magnetic field H. This contribution is of order α, where α is the Fröhlich electron (hole)‐LO phonon coupling constant (in the case H = 0 the cross section is of order α2). This α‐dependence results from the quasi one‐dimensional motion of the electron (hole) in a high magnetic field. For such a polar semiconductor as InSb (α ≈ 0.013 ≪ ≪ 1) a high magnetic field leads to a sharp increase of the secondary radiation intensity. The two‐phonon RRS cross section is an oscillating function of the magnetic field H and (or) of the incident light frequency ω1. The oscillations exist due to the increase of the density of states near the Landau zone bottom. It is shown that in the vicinity of a number of values of the magnetic field H = H0/L, where H0 = mecωLO/|e|, (me(e) = effective mass (charge) of electron, L = 1/2, 1, 3/2, 2, …, there is a number of additional contributions of interferential character to the cross section, which lead to a resonance decrease of the secondary emission intensity.