Electron spin resonance and related phenomena of low-dimensional electronic systems in III–V compounds

Abstract

In this work, dc and high-frequency transport phenomena directed primarily at spin properties in two-dimensional electronic systems (2DES) and the quantum Hall effect (QHE) are reviewed. The spin properties are probed by electron spin resonance (ESR). The experimental methods used are presented and the theoretical background based on k ⋅ p theory is given. The effects of further reducing the dimensionality are discussed in the context of experiments on zero-dimensional systems, ‘quantum dots’.To place this work in perspective, the ESR of ‘bulk’, three-dimensional systems and of strained bulk materials is also treated.Experimental results are presented to clarify the origin of the interaction between the 2DES and the electromagnetic radiation responsible for ESR. These results are compared with theoretical work on the electric dipole and magnetic dipole oscillator strength. The magnetic dipole interaction is found to dominate. The 2DES is subject to electron–electron interaction effects. While no influence on the resonance energy, in accordance with ‘Kohn's theorem’, is found, indications of many-body effects on the temperature dependence of the spin polarization of the ESR are observed. This is in accordance with other experimental and theoretical works which also found (or predicted) the formation of states with reduced spin polarization.While the influence of the interactions between electrons on the ESR frequency is absent, the hyperfine interaction between electrons and nuclei causes a shift (called the Overhauser shift) of the position of the ESR when the nuclei are spin polarized. Experimental results indicate that the appearance of this shift coincides with magnetic field regions where the plateaus of the quantum Hall effect are present.