A Comparative Study of Cyclotron Decay in Two-dimensional Electron Gas Samples.

We used THz time-domain spectroscopy to study cyclotron decay times in high mobility GaAs 2DEGs of varying well widths (30nm and 12 nm). All the measurements were done at a magnetic field of 0.8T as a function of temperature (0.4-10 K). We compare the characteristic cyclotron decay times in both types of samples, as a function of temperature, to examine the influence of surface scattering and strong quantum confinement. Our previous work has shown that the cyclotron decay time exceeds the single particle/quantum lifetime by \textasciitilde 60x in the 30nm 2 DEG QW[1], which we attribute to the influence of small angle scattering in the high-mobility limit $\mu $\textunderscore DC$=$3.6$\times$ 10\textasciicircum 6 cm\textasciicircum 2 V\textasciicircum (-1) s\textasciicircum (-1). [1]Jeremy A. Curtis et al., Physical Review B 93 (15), 155437 (2016).