In two-dimensional electron systems confined to wide AlAs quantum wells, composite fermions around the filling factor ν=3/2 are fully spin polarized but possess a valley degree of freedom. Here we measure the energy needed to completely valley polarize these composite fermions as a function of electron density. Comparing our results to the existing theory, we find overall good quantitative agreement but there is an unexpected trend: the measured composite fermion valley polarization energy, normalized to the Coulomb energy, decreases with decreasing density.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 6 2009|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics