V. E. Kozlov, A. B. Van’kov, S. I. Gubarev, I. V. Kukushkin, V. V. Solovyev, J. Falson, D. Maryenko, Y. Kozuka, A. Tsukazaki, M. Kawasaki, and J. H. Smet. Phys. Rev. B 91, 085304 (2015).
The plasma, magnetoplasma, and edge magnetoplasma excitations were investigated in two-dimensional electron systems hosted at the heterointerface of MgZnO/ZnO structures using optical detection of resonant microwave absorption. The magnetodispersion of the plasma excitations allowed the extraction of the electron effective mass. It was found to exhibit a surprisingly large dependence on the electron density, which is difficult to account for just from nonparabolicity effects.