Interaction of above-Fermi-edge magnetoexciton states from different subbands in dense two-dimensional electron magnetoplasma

Abstract

Photoluminescence spectra from 6-doped n-type A1~Ga&~As/In&Ga"As/GaAs quantum wells have been investigated in magnetic fields H(14 T and T=1.8-18 K. The Fermi level of the quasitwo-dimensional electron gas EF was slightly below the second subband. Interband Landau-level (LL) transitions between the j, th electron LL (j, =1,2) and the first hole LL, j, -l j"were analyzed. Their intensity was found to increase anomalously when the transition energy intersected that of the magnetoexciton state involving the electron from the second subband, 0,-0q. The intensity of the 0,-0& line oscillated with magnetic field and its maxima coincided with the intersection between the 0,-0j, energy and either the j, -0& or j, -1h transitions or both of them, depending on the energy separation between EI; and the second subband. Taking into account that the j, -1& and O, -OI, transitions involve no common particle, the anomalous behavior is explained by the interaction between two magnetoexciton states, 0,-0& and j, -l j, .

Pseudomorphic modulation-doped AlGaAs/InGaAs/GaAs heterostructures with strong manifestation of many-body effects

“…The Coulomb field from the 0 h hole state induces the admixture of the 0 e 2 state to the LL state, resulting in their enhancement because the oscillator strength for the allowed 0 e 2 → 0 h transition is more than two orders of magnitude larger [10]. In fact, the plateau is formed also for the 2 e → 0 h transition and the appearance of these plateaus gives evidence of complicated structure of the corresponding PL features, non-resolvable at the available magnetic field up to 7 T. We expect that at higher magnetic field the complicated interplay of the magnetoexciton states, 0 e 2 → 0 h and N e → 1 h might develop [36].…”

Oscillations of intersubband electron relaxation in aGaAs/Alx

“…5-10 So far, the study of magneto-optical oscillations was largely focused on the case of even filling factors. This was creative for understanding such phenomena as the band-gap renormalization in magnetic field, 11 the excitonic effects in a dense electron system, 5,6,9,10 and the oscillations of the intersubband relaxation of photoexcited nonequilibrium electrons. 7,8 Here we study the PL at a quantizing magnetic field of the electron system in a WSQW with front and back gates for changing its potential profile in the z direction.…”