Effects of photoluminescence polarization in semiconductor quantum wells subjected to an in-plane magnetic field

Abstract

Strong effects of optical polarization anisotropy observed previously in the quantum wells subjected to the in-plane magnetic field arrive at complete description within microscopic approach. Theory we develop involves two sources of optical polarization. First source is due to correlations between electron and heavy hole (HH) phases of ψ-functions arising due to electron Zeeman spin splitting and joint manifestation of low-symmetry and Zeeman interactions of HH in an in-plane magnetic field. In this case, four possible phase-controlled electron-HH transitions constitute the polarization effect, which can reach its maximal amount ( ±1) at low temperatures when only one transition survives. Other polarization source stems from the admixture of excited light-holes (LH) states to HH by low-symmetry interactions. The contribution of this mechanism to total polarization is relatively small but it can be independent of temperature and magnetic field. Analysis of different mechanisms of HH splitting exhibits their strong polarization anisotropy. Joint action of these mechanisms can result in new peculiarities, which should be taken into account for explanation of different experimental situations.

Linear polarization of the photoluminescence of quantum wells subject to in-plane magnetic fields

“…It may appear that the magneto-induced second harmonic A 2 H 2 cannot exceed the built-in polarization ℘ but, as was pointed out in Ref. [ 2 ] and as observed in experiment, the magnetic field-induced second harmonic can be much larger than the built-in polarization. This is possible within the framework of Eqs.…”

“…[ 2 ]. The concept of an extremely anisotropic (but pseudo-isotropic) hole g-factor has been verified by spin-flip Raman scattering (SFRS) experiments [ 3 ] and photoluminescence (PL) studies of charged single quantum dots [ 4 ], where the energy separation of the valence band spin sublevels was spectrally resolved.…”

“…(11)) includes the Luttinger parameter of the cubic anisotropy of the valence band g 2 (i.e., it follows Ref. [ 2 ]), the other version (Eq. (9)) does not require that parameter.…”

“…[ 2 ] have shown that the fourth harmonic of polarization can appear as a consequence the cubic anisotropy of the hole g-factor. If that is the case, the heavy hole states split linearly in the magnetic field even without the effect of an in-plane deformation.…”

“…Certainly, such corrections would have contributed to the amplitudes of harmonics (principally to that of the fourth harmonic [ 2 ], see also Eqs. (11)).…”