Fractional quantum Hall effect in CdTe

The fractional quantum Hall (FQH) effect is reported in a high mobility CdTe quantum well at millikelvin temperatures. Fully developed FQH states are observed at filling factor 4/3 and 5/3 and are found to be both spin-polarized ground state for which the lowest energy excitation is not a spin flip. This can be accounted for by the relatively high intrinsic Zeeman energy in this single valley two-dimensional electron gas. FQH minima are also observed in the first excited $(N=1)$ Landau level at filling factor 7/3 and 8/3 for intermediate temperatures. In contrast, the 5/2 FQH state remains absent down to $T\ensuremath{\sim}10\text{ }\text{mK}$.