Dolgopolov V.TMelnikov M.YShashkin A.AHuang S.-HLiu C.WKravchenko S.V.CHEE-WEE LIU2021-09-022021-09-02201800213640https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048567066&doi=10.1134%2fS0021364018120019&partnerID=40&md5=908b079cb7c39dd877f655f4aa311f84https://scholars.lib.ntu.edu.tw/handle/123456789/580624We have experimentally studied the fractional quantum Hall effect in SiGe/Si/SiGe quantum wells in relatively weak magnetic fields, where the Coulomb interaction between electrons exceeds the cyclotron splitting by a factor of a few XX. Minima of the longitudinal resistance have been observed corresponding to the quantum Hall effect of composite fermions with quantum numbers p = 1, 2, 3, and 4. Minima with p = 3 disappear in magnetic fields below 7 T, which may be a consequence of the intersection or even merging of the quantum levels of the composite fermions with different orientations of the pseudo-spin, i.e., those belonging to different valleys. We have also observed minima of the longitudinal resistance at filling factors ν = 4/5 and 4/11, which may be due to the formation of the second generation of the composite fermions. ? 2018, Pleiades Publishing, Inc.journal article10.1134/S00213640181200192-s2.0-85048567066