2008/11/30 by Atsushi Tsukazaki, A. Tsukazaki, Akira Ohtomo +19
Materials Science · Physics and Astronomy · #Ga2O3 and related materials #Quantum and electron transport phenomena #ZnO doping and properties #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.78.233308
published as Phys. Rev. B, 78, 233308 (2008). · 4 pages, 4figures, accepted for publication in Phys. Rev. B
arxiv created 2008/12/02 · openalex publication_date 2008/12/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report measurements of the spin susceptibility and the electron effective mass for two-dimensional electrons confined at the interfaces of MgxZn_1\ensuremath-xO/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\ifmmode×\else\texttimes\fi1011--1.6\ifmmode×\else\texttimes\fi1012 cm^\ensuremath-2, corresponding to a range of 3.1\ensuremath≤rs\ensuremath≤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.