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Two-subband system in quantizing magnetic field: Probing many-body gap by non-equilibrium phonons

V. M. Apalkov·M. E. Portnoi
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Abstract

We study the many-body effects in a two-subband quasi-two-dimensional electron system in a quantizing magnetic field at filling factor three. A manifestation of these effects in the phonon absorption spectroscopy is discussed. The electron system is mapped onto a two-level system with the separation between levels determined by the intersubband splitting and the cyclotron energy. The electron-electron interaction enhances the excitation gap, which exists at all values of the interlevel splitting. This results in a single-peak structure of the phonon absorption rate as a function of magnetic field, instead of the double-peak structure for non-interacting electrons.

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V. M. Apalkov, M. E. Portnoi. 2001-11-20. Two-subband system in quantizing magnetic field: Probing many-body gap by non-equilibrium phonons. https://doi.org/10.1016/s1386-9477(02)00554-4

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