Cyclotron resonance to 100 mK of a GaAs heterojunction in the ultra-quantum limit

Cyclotron resonance and spin states in GaAs/Ga1−xAlMichels1, Daly2, Gee3 et al. 1996Phys. Rev. BSelf Cite11020View full textAdd to dashboardCite

“…No anomalies in the effective mass are seen at fields corresponding to fractional filling factors. 2 Taken together, the 3 He and dilution refrigerator results provide strong evidence that the ground state of the 2DES contained within these samples is spin polarized throughout the FQHE region at fields above 4 T.…”

“…The majority of the experimental data to be presented correspond to Landau-level occupancies less than 1/6, where changes in the carrier density and temperature of the 2DES have been shown to dramatically affect the cyclotron resonance spectra. [1][2][3] This is also the occupancy region which is directly addressed by the CC model. 10 As has been mentioned in Sec.…”

“…These data were taken with the Fourier transform spectrometer for fixed values of field. The field range includes the fractions ϭ 2 3 to ϭ 1 3 , where strong features in transport have been observed in these samples. The spectra are regularly spaced with little variance in their absorption strengths or linewidths indicating the absence of any strong influence on the CR as the fractions are traversed.…”

“…5,7 Further work suggested that the origin of the two peaks was due to the spin splitting of the Landau levels rather than formation of the Wigner crystal. [1][2][3] The unusual temperature and density dependence, however, could not be explained by a single-particle picture. One possibility suggested to explain this behavior 3 was electronelectron interactions 8 or mode coupling.…”

“…CR is a spin-conserving effect and because the g factor in GaAs is energy dependent, the observation of two distinct transitions might be expected when both spinsplit halves of the lower Landau level involved are populated. 2 Initial experiments 4 looked for the expected splitting of CR in the region 1ϽϽ2; however, no splitting was observed. This negative observation was interpreted as the result of electron-electron interactions, and later in this paper we shall demonstrate that this surmise is correct.…”