Electrically detected magnetic resonance of two-dimensional electron gases in si/sige heterostructures

Strained (Formula presented) heterostructures, grown by solid source e-beam evaporation molecular-beam epitaxy on Si(100) substrates, have been studied by electrically detected magnetic resonance. Samples with a low-temperature mobility of about (Formula presented) were used, some with Schottky gates enabling control of the electron density in the channel. For (Formula presented) a conduction-band electron-spin-resonance signal caused by electron-electron scattering in the two-dimensional channel was observed in the dark. The signal intensity, g factor, and linewidth were observed to depend on electron density (Formula presented) and magnetic-field orientation. For (Formula presented) (Formula presented) (H parallel to the major conduction-band valley axis), and (Formula presented) (H perpendicular to major axis), which leads to an anisotropy of (Formula presented) For (Formula presented) the anisotropy nearly disappears. For (Formula presented) resonance linewidths as low as 70 mG are observed. A model for the resonant change in the conductivity is developed and compared to experiment.