Spin susceptibility and effective mass of two-dimensional electrons in MgxZn1-xO/ZnO heterostructures

Abstract

We report measurements of the spin susceptibility and the electron effective mass for two-dimensional electrons confined at the interfaces of MgxZn1-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 x 10^11 to 1.6 x 10^12 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.

4 pages, 4figures, accepted for publication in Phys. Rev. B

References in corpus (4)

• Measurements of the density-dependent many-body electron mass in 2D GaAs/AlGaAs Heterostructures
• Effective mass suppression in dilute, spin-polarized two-dimensional electron systems
• Spin Susceptibility of Interacting Two-dimensional Electrons with Anisotropic Effective Mass
• Dependence of persistent gaps at Landau level crossings on relative spin

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• Competition between fractional quantum Hall liquid and Wigner solid at small fillings: Role of layer thickness and Landau level mixing
• Density-controlled quantum Hall ferromagnetic transition in a two-dimensional hole system
• Determination of $g$-factor in InAs two-dimensional electron system by capacitance spectroscopy
• High-field Studies on Layered Magnetic and Polar Dirac Metals