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arXiv · 1810.11374

Direct observation of $Γ- X$ energy spectrum transition in narrow AlAs quantum wells

A. R. Khisameeva·A. V. Shchepetilnikov·V. M. Muravev·S. I. Gubarev·D. D. Frolov·Yu. A. Nefyodov·I. V. Kukushkin·C. Reichl·L. Tiemann·W. Dietsche·W. Wegscheider
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Abstract

Spectra of magnetoplasma excitations have been investigated in a two-dimensional electron systems in AlAs quantum wells (QWs) of different widths. The magnetoplasma spectrum have been found to change profoundly when the quantum well width became thinner than $5.5$~nm, indicating a drastic change in the conduction electron energy spectrum. The transformation can be interpreted in terms of transition from the in-plane strongly anisotropic $X_x - X_y$ valley occupation to the out-of-plane isotropic $X_z$ valley in the QW plane. Strong enhancement of the cyclotron effective mass over the band value in narrow AlAs QWs is reported.

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A. R. Khisameeva, A. V. Shchepetilnikov, V. M. Muravev, S. I. Gubarev, D. D. Frolov, Yu. A. Nefyodov, I. V. Kukushkin, C. Reichl, L. Tiemann, W. Dietsche, W. Wegscheider. 2018-10-26. Direct observation of $Γ- X$ energy spectrum transition in narrow AlAs quantum wells. https://doi.org/10.1103/physrevb.97.115308

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