We have studied the effect of the valence band structure on the fractional quantum Hall effect (FQHE) of two-dimensional hole systems (2D HS) in a symmetrically modulation-doped quantum well (QW). While keeping the hole density constant, we used front and back gates to vary the valence band structure in situ by changing the QW potential symmetry. The remarkable transitions we observed in the FQHE at v = 4/3 and 7/5 had a striking resemblance to the spin transitions reported for tilted-field experiments. We show that the effective g-factor determining the spin configuration of 2D HS in the FQHE is not a material-specific value, but reflects the valence band structure determined by the confinement potential of the 2D HS.
- Fractional quantum Hall effect
- Modulation doping
- Two-dimensional hole systems