Theoretical and experimental investigation of the effectivegfactor of donor-bound electrons in InSb

Abstract

Spin resonance of donor-bound electrons in n-type InSb is investigated experimentally and theoretically. The resonance is observed in far-infrared magnetotransmission experiments carried out in the wavelength range 96.5–151 μm on a series of samples with various doping levels. That the resonance is due to donor-bound electrons is established unambiguously from the dependence of the resonance intensity on temperature, magnetic field, and donor concentration. Owing to the extremely narrow linewidth of the resonance, the effective g factor of the donor electrons, $g_b$, can be determined very precisely and can be compared to the g factor of the conduction electrons, $g_c$. We formulate a theoretical model which predicts the behavior of $g_c$-$g_b$ in analytical terms. By fitting our experimental data to the model, we then obtain a set of parameters which completely describe the value, magnetic field dependence, and anisotropy of the effective g factor for donor-bound electrons in InSb. The observed anisotropy of $g_b$ is the same as that for $g_c$. The small difference in the anisotropies of $g_b$ and $g_c$ predicted by the theory is apparently less than the margin of error in our experiment.