Spin Polarization of Composite Fermions: Measurements of the Fermi Energy
Abstract
From the degree of circular polarization of the time-resolved radiative recombination of 2D electrons with photoexcited holes bound to acceptors we have measured the magnetic field dependencies of the electron spin polarization for various fractional ( ν = 2/3, 3/5, 4/7, 2/5, 3/7, 4/9, 8/5, 4/3, and 7/5) and composite fermions ( ν = 1/2, 1/4, and 3/2) states. The Fermi energies of these composite fermion states are measured for the first time and the corresponding value of the composite fermion density of states mass at ν = 1/2 is found to be about 4 times heavier than the previously reported values of the ``activation'' mass.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 1999
- DOI:
- 10.1103/PhysRevLett.82.3665
- Bibcode:
- 1999PhRvL..82.3665K