Spin susceptibility and effective mass of two-dimensional electrons in Mgx Zn1-x O/ZnO heterostructures

A. Tsukazaki, A. Ohtomo, M. Kawasaki, S. Akasaka, H. Yuji, K. Tamura, K. Nakahara, T. Tanabe, A. Kamisawa, T. Gokmen, J. Shabani, M. Shayegan

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Abstract

We report measurements of the spin susceptibility and the electron effective mass for two-dimensional electrons confined at the interfaces of Mgx Zn1-x O/ZnO single heterostructures (x=0.05, 0.08, and 0.11), grown by molecular-beam epitaxy on (0001) ZnO substrates. By tuning the built-in polarization through control of the barrier composition, the electron density was systematically varied in the range of 5.6× 1011 -1.6× 1012 cm-2, corresponding to a range of 3.1≤ rs ≤5.2, where rs is the average electron spacing measured in units of the effective Bohr radius. We used the coincidence technique, where crossings of the spin-split Landau levels occur at critical tilt angles of magnetic field, to evaluate the spin susceptibility. In addition, we determined the effective mass from the temperature dependence of the Shubnikov-de Haas oscillations measured at the coincidence conditions. The susceptibility and the effective mass both gradually increase with decreasing electron density, reflecting the role of electron-electron interaction.

Original languageEnglish
Article number233308
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume78
Issue number23
DOIs
Publication statusPublished - 2008 Dec 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Tsukazaki, A., Ohtomo, A., Kawasaki, M., Akasaka, S., Yuji, H., Tamura, K., Nakahara, K., Tanabe, T., Kamisawa, A., Gokmen, T., Shabani, J., & Shayegan, M. (2008). Spin susceptibility and effective mass of two-dimensional electrons in Mgx Zn1-x O/ZnO heterostructures. Physical Review B - Condensed Matter and Materials Physics, 78(23), [233308]. https://doi.org/10.1103/PhysRevB.78.233308